FIRE

(First ISCCP Regional Experiment)

IMPLEMENTATION PLAN

Prepared by the FIRE Science Experiment

July, 1985

Based on discussions at a series of FIRE Science Experiment Team meetings, an eleven-person Drafting Panel has prepared two documents that outline an approach for implementing the FIRE goals of basic understanding and parameterizations. The first document, the FIRE Implementation Plan (Abridged), is a condensed version that consists of two parts, an Executive Summary and an Overview of the FIRE tasks, observations, organization, data management, and priorities. It is intended for those readers who want a broad perspective of the FIRE goals, objectives, and approach.

The second document, the FIRE Implementation Plan, is similar to the Abridged version, but with expanded sections on the FIRE Research Tasks, Extended Time Observations, and Intensive Field Observations. It is intended for those readers who want a more detailed description of the research investigations and observations.

Additional copies of both documents are available from Mr. David S. McDougal, FIRE Project Manager, Mail Stop 483, NASA Langley Research Center, Hampton, VA 23665.

Page

1.0 EXECUTIVE SUMMARY 5

2.0 INTRODUCTION 7

3.0 FIRE RESEARCH TASKS 9

3.1 DEVELOPMENT OF CLOUD DESCRIPTION/CLASSIFICATION

SCHEMES 9

3.2 IMPROVEMENT OF CLOUD RADIATION MODELS 10

3.3 IMPROVEMENT OF SATELLITE CLOUD RETRIEVAL

TECHNIQUES 11

3.4 DESCRIPTION OF CLOUD SPACE/TIME STATISTICAL

STRUCTURES 12

3.5 IMPROVEMENT OF CLOUD DYNAMICS MODELS 12

3.6 IMPROVEMENT OF GCM CLOUD PARAMETERIZATIONS 14

4.0 EXTENDED TIME OBSERVATIONS 15

4.1 EXTENDED AREA 15

4.11 Satellite Observations 15

4.12 Surface Observations 17

4.2 LIMITED AREA 18

4.21 Satellite Observations 18

4.22 Surface Observations 18

4.221 Cirrus Studies 18

4.222 Stratocumulus Studies 21

5.0 INTENSIVE FIELD OBSERVATIONS 23

5.1 CIRRUS INTENSIVE FIELD OBSERVATIONS 23

5.11 Specific Objectives 23

5.12 Schedule 23

5.13 Location 24

5.14 Satellite Observations 24

5.15 Aircraft Observations 24

5.151 NASA/ER-2 Instrumentation 24

5.152 NASA/CV-990 Instrumentation 25

5.153 NCAR King Air Instrumentation 26

5.16 Surface Based Observations 26

5.17 Operations 26

5.2 STRATOCUMULUS INTENSIVE FIELD OBSERVATIONS 27

5.21 Scientific Objectives 27

5.22 Schedule 27

5.23 Location 29

5.24 Satellite Observations 29

5.25 Aircraft Observations 29

5.26 Surface Observations 31

5.27 Operations 33

6.0 FIRE SCIENTIFIC ORGANIZATION 35

6.1 FIRE WORKING GROUPS 35

6.2 INTENSIVE FIELD PROGRAM MANAGEMENT 35

6.21 Operations Plan 35

6.22 Mission Selection Team 36

6.23 Mission Planning Team 36

6.24 Mission Scientist 36

6.3 INTERNATIONAL COLLABORATION POLICY 37

7.0 FIRE DATA MANAGEMENT 38

7.1 DATA MANAGEMENT RESPONSIBILITIES OF PRINCIPAL

INVESTIGATORS 38

7.2 DATA MANAGEMENT RESPONSIBILITIES OF THE FIRE

WORKING GROUPS 38

7.3 DATA MANAGEMENT RESPONSIBILITIES OF THE FIRE

CENTRAL ARCHIVE 39

7.4 DATA MANAGEMENT RESPONSIBILITIES OF THE FIRE

PROJECT OFFICE 39

7.5 FIRE DATA PROTOCOL 40

7.6 FIRE DATA CHARACTERISTICS 40

8.0 FIRE DATA ACQUISITION PRIORITIES 41

REFERENCES 43

APPENDIX A

Description of NASA ER-2 Instruments 46

APPENDIX B

Description of UW C131-A Instruments 50

APPENDIX C

Description of NOAA WP-3D Orion Instrumentation 51

APPENDIX D

Description of NASA CV-990 Instruments 56

APPENDIX E

Description of NCAR King Air Instrumentation 57

APPENDIX F

Surface Measurements of San Nicolas Island 58

APPENDIX G

NOAA/WPL Ground-Based Remote Sensors 60

APPENDIX H

Glossary of Acronyms 63

APPENDIX I

Schedule of Significant FIRE Events 65

A more restrictive definition of FIRE's goals focusing on cirrus in the midwestern U. S. and marine stratocumulus cloud systems off the west coast of the U.S. has been adopted in light of the resources likely to be available for FIRE; cirrus and marine stratocumulus cloud systems were singled out because of their very significant climatic influences and because of the likelihood that FIRE could achieve significant research progress in these areas.

FIRE research and data acquisition will be performed by scientists from U. S. government agencies and from universities. NASA will serve as the lead agency with the FIRE Project Office located at the NASA Langley Research Center. A FIRE Science Experiment Team has been selected consisting of 36 scientists who have expressed strong interest in FIRE and who have participated in the planning of FIRE. In addition, FIRE Working Groups are to be formed to address some specific, complicated tasks requiring coordination of researchers with a variety of specializations and using multiple data sets.

Physical process modeling, which includes all processes important to the characterization and evolution of cloud systems, and large scale GCM and climate modeling are critical to FIRE'S success; these extremely important modeling components will be integrated into FIRE through the participation of modeling researchers in the FIRE Task Groups. In this way modelers will participate in all phases of FIRE.

FIRE includes two basic data gathering components: Extended Time Observations and Intensive Field Observations. The Extended Time Observation data set consists of satellite data, meteorological analyses and data from a limited number of surface observing sites. Satellite data from 50° N to 50° S and from 60° to 140° W will be collected on a 6 day on- 9 day off schedule for a four-year period beginning in January, 1986. Northern hemisphere meteorological analyses for this period will also be archived. In addition, at least three sites will be maintained which will include surface instrumentation measuring downwelling radiation components and meteorological variables. Two of these sites will have lidar installations. The sites chosen to date are San Nicolas Island for marine stratocumulus studies and Salt Lake City, Utah and Boulder, Colorado for cirrus studies.

The Intensive Field Observations will consist of three- to six-week field experiments concentrating on multiplatform, high space and time resolution observations of cirrus and marine stratocumulus cloud systems. The cirrus observations will be collected in the midwestern U. S. with the first experiment scheduled for Fall, 1986 in central Wisconsin. A second phase of the cirrus Intensive Field Observations will be conducted in early Spring, 1988; the exact site has not yet been chosen. The marine stratocumulus Intensive Field Observations will be conducted in the vicinity of San Nicolas Island, off the West Coast of the U. S.; the first marine stratocumulus experiment is scheduled for early Summer, 1987 with a second observation period in Summer, 1989.

The cirrus and marine stratocumulus Intensive Field Observations will require extensive satellite data support. Both will rely upon air craft for in situ sampling of microphysical, thermodynamic and radiative properties of the cloud layers. Two NASA jet aircraft will be utilized in both programs. Both programs would benefit from at least one additional aircraft capable of measuring air motions and cloud microphysics; aircraft from NCAR and NOAA are currently being sought to fill this need. Both the cirrus and stratocumulus programs will require surface observations of radiation and lidar information about the cloud layer; a tethered balloon installation is crucial to the marine stratocumulus experiment and a 50 MHz doppler sounding instrument currently under development would be highly complementary to the cirrus experiment. In addition, each experiment will require supplementary rawinsonde accents.

Satellite data and some routine meteorological data from the Extended Time Observation component of FIRE will be centrally archived. In addition, some of the surface lidar and radiation data will be submitted to an archive for use by the scientific community; this latter type of data will be of the value-added variety where principal investigators have spent considerable effort in reducing subsets of their raw data for widespread utilization. From the Intensive Field Observations satellite data and selected value-added data sets resulting from FIRE Working Groups' activities will be centrally archived. Several institutions are currently being considered to hold both the Extended Time and Intensive Field Observation data sets; chief among the factors being considered in this selection are ease of access and quality assurance. From time to time, certified FIRE data will be transferred to EDIS and/or other organizations for permanent archive and for open access by the at-large scientific community.

FIRE will improve GCM cloud-radiation parameterizations, for at least cirrus and marine stratocumulus clouds, by providing a better understanding of the link between small scale cloud processes and planetary scale climate processes. This goal will be accomplished by the extensive interaction in FIRE between scientists specializing in observational analysis and those with expertise in multiple scales of atmospheric modeling.

The FIRE Science Experiment Team (FSET) has taken the charge "... to quantify the capabilities of current models for large scale cloud systems and for their effects on radiation, and to obtain data and understanding necessary to improve these models...", and focused it to produce a three-pronged scientific experiment described in this document, THE FIRE IMPLEMENTATION PLAN. The three components are: 1) investigation of cirrus cloud systems; 2) investigation of marine stratocumulus cloud systems; and 3) investigation of interrelations between ISCCP data and higher time and space resolution cloud data. In this implementation plan specific objectives and strategies for each of these three components are set forth. In fact, the three components are highly interactive in all phases of planning, execution and analysis. Many activities cited in the marine stratocumulus and cirrus plans directly support the ISCCP intercomparison goals; the period of the cirrus and marine stratocumulus activities are designed to coincide with the period of the ISCCP program, which is expected to continue until 1988 or possibly 1989; and some data collected during the marine stratocumulus field program will be highly complementary to the cirrus program and vice versa. In fact, the three components of FIRE are so closely related that a common set of general goals and strategies for all three may be defined.

These goals for FIRE may be simply stated as:

GOAL 1: BASIC UNDERSTANDING: The first goal common of the three components of FIRE is an understanding of roles played by physical processes in determining life cycles of cirrus and marine stratocumulus cloud systems and the radiative properties of these clouds during their life cycles. Specifically, FIRE has been designed to address the study of the formation, maintenance and dissipation of cirrus and marine stratocumulus cloud systems. In both types of cloud systems, cloud radiative properties play important roles in the energy budgets of the cloud layers themselves, in the planetary energy budget and in any cloud layer parameters inferred remotely from satellites. In this lest sense, this objective addresses needs of the ISCCP data set.

GOAL 2: PARAMETERIZATION: A second common goal among the FIRE components is a quest for relationships between large scale processes, or representations, and smaller scale processes, or representations; the primary reason for employing this approach is that we have a better physical understanding of and ability to investigate cloud scale phenomenae, although climate models cannot explicitly resolve these cloud scale processes. For the cirrus and stratocumulus cloud systems, relationships between the cloud scale processes and the climate scale model variables will become the future parameterizations in a GCM or climate model; in the case of ISCCP data, these relationships will lead to a better understanding of and increased utilization of ISCCP data by the scientific community.

The FIRE IMPLEMENTATION PLAN outlines a series of investigations and observations designed to meet the goals of basic understanding and parameterization. In this plan, FIRE is not meant to solve "all" of the problems in the field of clouds and radiation. Rather, FIRE is meant to address the issues of basic understanding and parameterization of cirrus and marine stratocumulus cloud fields and ISCCP data products.

Besides sharing a common set of goals, the three FIRE components share a general set of strategies adopted to achieve those goals. These three common strategies are briefly set out below:

Strategy 1: MODELING - The modeling strategies for FIRE encompass several types of models. These models range from radiative transfer models which require cloud microphysical data as input, to cirrus and marine stratocumulus models capable of describing the time evolution of these cloud systems, to general circulation and climate models, which will ultimately utilize cloud parameterizations, and to the retrieval algorithm models utilized in ISCCP. All FIRE modeling strategies seek first to provide a means to compare our best current understanding of a phenomenon with observations of that phenomenon and second to provide a means to extend that understanding by utilizing the models to extrapolate to other conditions.

Strategy 2: EXTENDED TIME OBSERVATIONS - We have much to learn from data bases already collected and those currently being collected; this is particularly true for satellite data and to a lesser extent for other types of data. The extended time observations of cloud systems will yield information on the phenomenology of these systems, on their variability in space and time, and on their bulk radiative properties. Since these data will generally be of higher spatial resolution than the ISCCP data set, they will be particularly useful for comparison with ISCCP products.

Strategy 3: INTENSIVE FIELD OPERATIONS - Intensive field programs are currently planned to support all three components of FIRE. Four field programs of three to six weeks duration are planned. These field programs are designed to observe cloud systems with high resolution temporal and spatial sampling. The field programs will include satellite, aircraft, balloon borne and surface observations. The experiments will be concentrated in limited geographical areas for periods of three to six weeks. Four intensive field programs are planned; one each year beginning in Fall 1986. The 1986 and 1988 field programs would be staged in the continental U. S. with an emphasis on the study of cirrus systems; 1987 and 1989 experiment would emphasize marine stratocumulus systems and be staged near San Nicolas Island, off the west coast of California. Although the intensive field operations would emphasize the cirrus and marine stratocumulus objectives, they would also strongly contribute to the ISCCP intercomparison objective.

1. Improve cloud radiation models.

2. Improve cloud dynamics models.

3. Intercompare the ISCCP cloud climatology with FIRE cloud data.

Each of these steps is to be carried out for marine stratocumulus and cirrus clouds as part of two types of studies: (1) The intensive field observations programs (IFO) will collect and analyze limited area/time data focused on the diagnosis of cloud processes at smaller scales; (2) Extended time observations (ETO) will collect and analyze regional, multi-year data to bridge the gap between IFO and ISCCP data. The unique attribute of the FIRE IFOs is the coordination of satellite, aircraft and ground observations. This section outlines the specific tasks planned as part of FIRE.

Comparisons of data and models on many different scales require a common description or classification of cloud types to insure comparison of the same cloud phenomena. Selection of case studies from a larger data set also requires a method for rapid identification of cases involving a particular cloud type. Most cloud classifications (e.g., WMO instructions for ground observers) are based on cloud morphology on scales ~0.1-10 km; however, for FIRE the cloud type definitions must be applicable to all space and time scales covered by the different observations. Improvement of GCM cloud parameterization also begins with identification of the cloud types which behave in distinctly different ways.

Available studies have identified four crucial properties of clouds that distinguish the effects of different clouds on observed radiances, namely, (1) cloud size distribution, (2) cloud element shape and texture, and (3) internal variability within a cloud element, and (4) cloud microphysical structure. Cloud size distribution describes the characteristic size (or size range) of individual cloud elements; e.g., cumulus and stratus clouds exhibit a very different relation of cloud element size to the mesoscale or synoptical scales of atmospheric motions. Cloud element shape and texture significantly affect the angular distribution of reflected solar radiation (Busygin et al., 1973; McKee and Cox, 1976; Davis and Cox, 1982; Harshvardan, 1982; Welch and Wielicki, 1984; Schmetz, 1984 and Davies, 1984) and of emitted thermal radiation (Naber and Weinman, 1984). Variations in liquid water content between cloud elements or within individual elements can have similar effects (Coakley and Bretherton, 1982; Wielicki and Welch, 1985). Cloud microphysical structure--as represented by particle composition, size, shape, phase, and possible internal inhomogeneity (or the distribution functions for these parameters)--determine the particle scattering and absorption properties as functions of wavelength, and thereby plays a role in determining the cloud's large scale radiative properties (Wiscombe et al, 1984).

Development of a cloud classification scheme will be a continuing effort throughout FIRE. Data collected during FIRE that provides a measure of the four parameters described above must be compared with other classifications and modeling studies to identify the key patterns that meaningfully distinguish cloud types. A link to the familiar morphological cloud types will be provided by photography from all ground-based and aircraft-based observing platforms.

(Step 1 and 4)

This task addresses the problem of calculating the radiative effects of clouds given a specification of cloud properties. The primary issues are to determine which properties are most crucial to accurate calculations of radiation and to ascertain the sensitivity of radiative calculations to cloud parameters that are difficult to measure. Since most cloud radiation models involve approximations, for example ignoring small scale variations in liquid water content, this task is also concerned with testing such approximations. The strategy for FIRE is to assemble data sets which contain both specifications of cloud and atmospheric properties and independent verification measurements of the radiation field produced by the clouds. The former are needed to define the clouds in the radiative transfer model (input) and the latter are used to verify the calculated radiation (output). The observations must be balanced between input and output parameters to provide definitive tests of model performance. These data will be used to test various types of radiative models, particularly column models and full three-dimensional models. Intercomparisons of the models provides further insight for parameterization of cloud-radiation effects in GCMs.

The key parts of this task are as follows:

(Steps 1, 3 and 4)

This task addresses the problem of inferring cloud properties from measured radiances that is central to the analysis of FIRE observations and constitutes a major contribution to the interpretation of the ISCCP cloud climatology. Improvement of radiative models that relate cloud properties to observed radiances is not only intimately linked to the general understanding of the cloud-radiation interaction in Steps 1 and 4, but also includes specific problems raised by the analysis of satellite data in ISCCP. Satellite-measured radiances are generally limited in spatial and temporal resolution, angular coverage, and spectral coverage; thus, retrieved cloud parameters using current methods depend on these factors (Rossow et aI., 1985). These factors also present a challenge to the coordination of satellite data with other observations for retrieval validation. The IFO observations must be coordinated to provide a balanced set of input radiances and output cloud properties to test retrieval techniques. Limited intercomparisons using ground-based and aircraft observations must also be extended to larger scales by statistical comparisons of mufti-satellite data. Comparisons of retrievals by different techniques applied to the same FIRE and ISCCP data are a key to development of better methods.

Key cloud properties retrieved by current methods that will benefit from intercomparisons are:

The FIRE IFOs provide the coordinated observations of target cloud types (marine stratocumulus and cirrus) from "round, aircraft and spacecraft needed to obtain the nearly simultaneous and coincident measurements of cloud properties and radiances to test radiative and cloud dynamics models. The ETO extends these detailed results to larger space and time scales using very high resolution observations and connects them to the more extensive, but longer resolution ISCCP and ERBE results. This extension is necessary to determine the representativeness of the results and to provide the type of information needed by radiative and cloud dynamical models that parameterize the smaller-scale cloud property variations. Close coordination between the IFO and ETO is required.

Key parts of this task are as follows:

This task concerns the understanding of the processes that produce clouds from particular atmospheric stases. The special emphasis of FIRE is to extend our understanding of the workings of these processes on the smaller space/time scales of individual clouds to cloud structures and the state of the atmosphere on meso- and synoptic scales. The primary data for this task will be that obtained during the IFOs targeted on marine stratocumulus and cirrus; however, the ETO, based largely on satellite data, is necessary to link small scales to large scales. This task also depends on radiative model improvements to increase the detail retrieved form the IFO and ETO data. The emphasis is on model comparisons to data to diagnose processes and to improve modeling of these two cloud types.

Cirrus clouds exhibit significant horizontal and vertical structure and a strong coupling to radiation (Starr and Cox, 1985). Little is known about the distribution of cirrus, the conditions required to produce them, or their life cycles. The primary focus of this task is to improve understanding of the coupling of cirrus clouds, radiation, and atmospheric dynamics by comparisons of models to coordinated measurements of all of these quantifies. Models that will be employed for these studies include two-dimensional (horizontal/vertical) time dependent process models, high-resolution, Iimited-area models and GCMs. The coordination of "round, aircraft and satellite observations during the IFOs, as well as the extension of the IFO results to the ETO and ISCCP scales, is crucial to this task.

Key issues to be studied are as follows:

i. Space/time structure of cloud properties.

Marine stratocumulus clouds exhibit considerable structure from the smallest scales (~1 km) resolved by satellites (Coakley and Bretherton, 1982) to mesoscale/synoptic scale (Agee et aI., 1973). However, only a few modeling and in situ observational studies have focused on fractional cloudiness (Sommeria and Deardorff, 1977; Albrecht, 1981; Bougeault, 1982). A major focus of this task is to elucidate the processes responsible for determining fractional cloud cover through comparisons of models to FIRE data. A broad spectrum of dynamical models will be employed, including simple mixed-layer models, "large" eddy models that explicitly resolve the primary turbulent motion scales, high resolution, limited area dynamical models and GCMs that include boundary layer and cloud parameterizations. Microphysical models will also be used to investigate the coupling between dynamics and radiation through cloud radiative properties.

Key issues to be studied are as follows:

This task includes many of the activities discussed above but the emphasis is on the climate GCM calculation of radiative flux divergences from a particular large scale atmospheric state involving clouds. The FIRE concept breaks this calculation into two parts: calculation of cloud properties from an atmospheric state and calculation of radiation fields from cloud properties. The primary focus of this task within FIRE is to define quantitative methods for comparison of data and models; this is an appropriate FIRE task because of the detailed study within FIRE to understand the linkage between IFO and ETO data and between these data and specific process models. The FIRE data sets allow for GCM tests in both prognostic and diagnostic modes. FIRE and ISCCP data, together, provide a check of the statistical behavior of GCMs, while FIRE and ERBE provide a check on the statistics of the GCM radiation budget. Comparisons of data to GCMs must build on the FIRE developments that link multi-scale observations and model results and develop methods for comparison of cloud properties, radiation quantifies, and the space/time statistics of these.

The Extended Time Observations are subdivided into two space scales: Extended area and Limited area. The extended area data set is meant to provide data over a large geographical area where occurrences of cirrus and stratocumulus cloud systems may be found in a variety of geographical locations; and to allow for mufti-satellite, multiple-vie" observations of these systems. The limited area data set is geographically specific to the location and surrounding area of surface observing sites being maintained throughout the FIRE experiment.

The specific objectives of the ETO are:

Statistical descriptions of cirrus and marine stratocumulus cloud fields will be multi-dimensional frequency distributions on a spatial scale of (250 km)² . These distributions will characterize cloud field properties including areal cloud fraction, cloud top height and temperature, cloud visible reflectance and shortwave albedo and cloud infrared emittance.

Within each month of the year, data will be collected for 6 days on, 9 days off, and 6 days on, etc. This sampling will allow some time dependent studies of cloud evolution, while obtaining independent synoptic meteorological samples. The 6 days on and 9 days off cycle is dictated by the NOAA polar orbiter ground track repeat cycle of 9.5 days. By allowing 9 days off between sampled for any geographic area within one month. In order to simplify data collection planning, the two 6 day periods will be taken on the 5th to 10th days and the 20th to 25th of each month.

The satellite data to be included in the FIRE ETO-EA archive is given below:

Data for extended area, extended time satellite observations will be extracted from the NOAA/NESDIS archive on an as needed basis. It is expected that data for multiple-satellite, multiple-view studies of the directional properties of the cloud radiance field will focus on daytime only data and of that only conjunctions of satellite observations that allow simultaneous views of individual cloud systems. Such a study compacts the overall extended area, extended time observations to a set of approximately 20 6250 BPI tapes/year containing the required AVHRR, HIRS, VISSR/VAS data.

The description of the downwelling radiation fields and the conventional meteorological fields will be constructed primarily from observations and analyses which are routinely available. The NOAA/NWS and northern hemisphere international rawinsonde networks (~90 sites) and the U.S. Solar Radiation Network (NOAA/ERL) will provide the extended area surface and upper air data. However, satellite derived information on standard meteorological fields (soundings and wind fields) will be incorporated into the data sets for the regions within the FIRE domain which are not well-sampled by the rawinsonde network; this is currently clone operationally by the NOAA/NMC using products provided by NOAA/NESDIS. These data are operationally archived by NOAA and will be added to the FIRE archive when acquired for specific FIRE studies.

The surface observation data sets are:

Note that HIRS-2, VAS Sounder, ERBE, AVHRR-GAC, and ISCCP data can be obtained for the same times using a subset of the ETO-EA data set.

While the ]imited area extended time observations represent a sizeable archive (-200 6250 BPI tapes/year), it is recognized that intensive analyses will be limited to a 10-20% subset of this data; over a four year period this subset will contain approximately 100 statistically independent samples of appropriate cirrus and stratocumulus cloud systems.

The approximate locations of the three proposed class I observing sites are Salt Lake City, Utah; Hampton, Virginia; and Boulder, Colorado. Other potential class I observing sites exist both within the United States and in other countries. It is recommended that observations be taken at these locations and analyzed according to the strategy and objectives of this program to the extent that this is possible.

Class I sites will be operated throughout the duration of FIRE (4 years). Observations will be taken when cirrus clouds are present and generally unobstructed by extensive underlying cloud layers. At each site, observations will be taken at one second intervals during at least one continuous three hour time period on at least three days of most weeks subject to the occurrence of suitable conditions. Observing times should be coordinated with the 6-day on phase of the satellite observing schedules when possible in order to maximize the acquisition of coincident satellite and surface based observations.

In order to document suspected day-night differences in the structure and properties of cirrus, 25% of the schedule observing periods should be at night. Thus, a sample of ~2500 hours of observations with 500 of these occurring at night is planned (9 hours/week for ~35 weeks/year over 4 years at 3 sites.

Details of the instrumentation, which will be in place at the class I observing sites, is somewhat site specific. However, the following instrumentation and support facilities will exist at each of the sites:

These instrumentation facilities will provide measurements of the direct and total downwelling solar radiation at the surface and vertical profiles of environmental pressure, temperature, humidity, and horizontal winds. Occasional supplementary rawinsonde launches will be required in addition to the usual, twice daily, routine launches. On average, one supplementary launch per week per site is likely to be required. A minimum 12 hour advance notice for a special launch will be needed from the special observing sites. The lest two items, which are support facilities, will assist a local 12-36 hour forecast to be made at the site. This will be used in scheduling observing periods, requesting special rawinsonde launches and coordinating with satellite observations. Details of the additional site-specific instrumentation are given below for each site.

The corresponding directly calculable cloud physical properties are (i) cloud base and top heights, areal cloud fraction, particle phase and ice crystal orientation, and cloud optical depth at .694 µm; (iii) cloud type and amount. The corresponding inferentially calculable cloud properties are (i) broadband visible cloud optical thickness and ice crystal habits; (ii) cloud emittance at 10-12 um and broadband infrared cloud emittance; (iv) cloud (ice) water content (occasionally).

The corresponding directly calculable cloud properties are (i) cloud base and top heights, areal cloud fraction, particle phase and ice crystal orientation and cloud optical thickness at 694, 347, and 532 nm; (ii-iii) cloud optical thickness at multiple wavelengths from 0.4-2.2 µm; (iv) surface radiation budget (v) cloud type and amount.

The corresponding directly calculable cloud properties are (i) cloud base and top heights, areal cloud fraction, particle phase and ice crystal orientation and cloud optical thickness at 694, 347, and 532 nm; (ii) ice particle fall speeds, turbulent intensity and vertical profiles of horizontal convergence/divergence; (iv) broadband visible cloud optical thickness. The corresponding inferentially calculable cloud properties are (i) broadband visible cloud optical thickness and ice crystal habits; (ii) local vertical profile of vertical wind speeds and ice crystal habits; (iii) cloud emittance at 10-12 µm and broadband infrared cloud emittance; (iv) areal cloud fraction.

Class II sites will be operated continuously during daylight hours throughout the duration of the FIRE ( 4 years). Seven class II sites are planned. Proposed class II sites are:

Boulder, Colorado

Champaign, Illinois

Hampton, Virginia

Mauna Loa, Hawaii

Madison, Wisconsin

Palisades, New York

Salt Lake City,-Utah

West Lafayette, Indiana

It should be noted that the Utah and Boulder class I sites are colocated with a class II site. This colocation will provide an observational basis for developing inferential relationships between cloud properties deduced from Lidar observations and the passive measurements made at a Class II site.

At each of the class II special observing sites, most of the following instrumentation and support facilities will be in place:

i. multiple field-of-view, solar (visible) radiometer

ii. pyranometers

iii. NWS rawinsonde site (close proximity)

iv. data logging facilities.

These instruments will provide a direct measurement of (i, ii) the broadband visible cloud optical depth and the direct and diffuse components of downwelling visible radiation; (ii) the total downwelling solar radiation at the surface, and (iii) the environmental profiles of pressure, temperature, humidity, and horizontal winds - no special launches required. Inferentially, an estimate of local cloud cover or cloud structure (variability of visible optical depth over sky) may be made based on observations (i).

The Naval Postgraduate School and the Naval Research Laboratory are planning to cooperate with several universities in a multi-year field program of nearly continuous Cloud Top Boundary Layer (CTBL) studies at SNI, involving the installation of a three wind component Doppler Sodar, and augmentation of the tower with a full suite of longwave and shortwave surface radiation measurements. An existing network of radiosonde stations (two island, four coastal) will be used to define horizontal variability and longer tropospheric thermodynamics.

NOAA/ERL is planning to make extended-time surface radiometric measurements at SNI. Automated pyranometers and pyrheliometers will be located at the vertices and at the center of a 5-point square network occupying approximately a two square mile area. More complex and some manually-operated instruments will also be located at the center of the network to make additional measurements for giving more detailed spectral information. Portable, independent, and weather-proof data acquisition systems will be located at each vertex. Spectral measurements of solar transmission will also be made. An automated scanning radiometer with three spectral charnels will be used. Also, pyrogeometer measurements of the downwelling longwave flux will be made. Depending on the success of testing now in progress, solar radiometersondes may be periodically flown vertically through the stratus deck to obtain the vertical upwelling and downwelling flux profiles for comparison with model calculations.

A summary of planned observations is given in Table 1

The sampling strategy involves obtaining observations of the same targets from multiple platforms. Synchronized high resolution multispectral satellite observations will be obtained from multiple platforms viewing the scene from different angles. Coincident observations will also be obtained from aircraft where one is essentially a satellite platform simulator with additional capabilities and the other aircraft are equipped with in situ radiative, microphysical and air motion sensing instrumentation. Special lidar, radar and radiometric observations will be obtained from surface based sites as will conventional observations of meteorological parameters. The strategy calls for high density observations over limited times (2-3 hours) both in small (10 km)² fixed regions where surface based observations are being collected and over surrounding regions as weather and satellite operations permit. Observations over the fixed region will serve the purposes of the intensive case Studies while missions over the surrounding regions, particularly over water, will provide important data for cloud retrieval algorithm intercomparison.

Since relatively little is known about cirrus clouds, it is appropriate to pose a number of key questions that will require answering before the central objective can be met. These questions include:

The above list is not meant to be exclusive; it is offered only to illustrate how much is not presently known about cirrus clouds and therefore, how much we have to gain from the FIRE cirrus component.

Two field experiments are planned with the first in the Fall, 1986 and the second in early Spring, 1988. Each will be three to six weeks in duration. A target of sixteen case study samples should be attainable in this two stage experiment setting. The observing periods will provide the opportunity to sample pre-warm frontal and jet stream cirrus in 1986 and convectively generated cirrus and jet stream cirrus in 1988. Furthermore, the two observational periods will provide an opportunity for researchers to revise strategies and instrumentation based on the experience and results of the first experiment. This is particularly important for the cirrus observational studies since this will mark the first major experimental effort concentrating on cirrus cloud systems.

The site for the second phase of the experiment has not yet been selected. Possible locations are a longer latitude location in the Midwest U.S. or even the same site as the first experiment. This decision will be made following the experience obtained in the first experiment.

It should be noted that the nominal horizontal resolution/sampling interval is -100 m or less for most airborne systems. The cloud lidars will generate a high resolution description of cloud base and top heights, areal cloud fraction, particle phase and orientation and cloud optical depths at the sampled wavelengths. Other radiometric instrumentation will serve to define the upwelling and downwelling broadband fluxes and spectral radiances. The aircraft observations will also permit direct analysis of the fine-scale structure of the upper lever humidity and motion fields.

Table 2

winds Gust probe, inertial navigation system

temperature Rosemount, NCAR, reverse flow, fast response,

radiation

water vapor Lyman-Alpha hygrometer

liquid water Knollenberg, and Johnson-Williams liquid

droplet distribution water

shortwave and longwave Barnes PRT-5, Eppley pyranometers and

irradiances pyrgeometers

sea surface temp Barnes PRT-5

ozone Pearson-Stedman (see Lenschow et aI., 1981)

Because of the importance of relating the observed cloud and radiative fields to the large scale meteorological conditions and the difficulty of obtaining good estimates of large scale vertical motion at cirrus cloud levers, it is proposed that two independent wind sounding systems be deployed over the intensive field observing region. The first is the conventional rawinsonde network that will be operated by NOAA/NWS. Coordinated on-demand launches will be required of all these sites during times when aircraft missions are in progress. The affected stations would be St. Cloud, MN; International Falls, MN; Green Bay, WI; Peoria, IL; Sault St. Marie, MI; and Flint, MI. In addition, two special stations would be required in the observing -region (western edge). These supplementary rawinsonde sites will permit consistency checks between vertical motion computed from observed horizontal divergence determined over triangular regions encompassing the field region and its nearby environment as well as corrections for sonde drift.

The second upper-level wind system is a VHF wind profiling system (Appendix G) being developed by NOAA/ERL. These systems are unaffected by problems of sonde tracking and drift and may provide an accurate direct measurement of ambient vertical motion over each unit. In addition, horizontal wind speeds and directions can be observed which may then be used to infer larger scale vertical motions in much the same way as is clone for rawinsonde observations. Continuous sampling allows time averaging that ensures a much greater degree of representativeness than rawinsonde observations offer To achieve high accuracy at cirrus cloud levers, wind profilers should be operated at a frequency of 50 MHz. Ideally three of these sites would be operated within the field region provided resources can be found to support this activity. At the very least, one profiler would be very useful to provide a detailed description of the convective structure of the overlying cirrus cloud.

A forecasting capability is crucially important to field operations. Specific forecasting responsibilities will be assumed by members of FSET. Facilities at the University of Wisconsin at Madison will be utilized., i.e., McIDAS, to enable 12-36 hour forecasts and longer range outlooks to be generated for the observing region. In this respect, it should be noted that quick look data sets will be available from all observing systems in the field to facilitate mission planning. Aircraft missions may be flown on successive days or on a day/night sequence as may be required by weather conditions and satellite operations. All surface observing systems will be maintained in an on call basis throughout the field experiment period.

o What determines the fractional cloudiness and cloud morphology?

o What determines the magnitude of the entrainment rate?

The intensive phase will provide the opportunity for a three-platform intercomparison study. Ground, aircraft and satellite measurements will be combined to infer the effects of processes that are extremely difficult to measure directly. For example, aircraft radiation measurements taken above the clouds will be combined with satellite measurements to deduce free-atmospheric radiative heating/cooling rates; likewise, "round and aircraft data will be used to deduce whole boundary layer heating rates.

A full spectrum of modeling studies will continue throughout the experiment. There will be many opportunities for comparisons of field observations with model results.

The use of satellite observations to characterize the CTBL can begin immediately, using archived data. The field experiments, however, will be preceded by a period of preparation, in order to allow time for the planning and development of suitable data acquisition and processing techniques.

TABLE 3. SCHEDULE OF ACTIVITIES FOR THE FIRE STRATOCUMULUS SUBPROGRAM.

1985 1986 1987 1988 1989 1990

THEORETICAL AND MODELING STUDIES X X X X X X

EXTENDED-TIME OBSERVATIONS (SATELLITE) X X X

INTENSIVE FIELD-EXPERIMENTS X X

ANALYSIS OF OBSERVATIONS X X X X

Experimental planning during the intensive period will be greatly facilitated by the use of an interactive satellite data processing and display system available at SNI. The facility can also be used for limited data archival.

Table 4 lists the aircraft that will potentially be available to the FIRE Stratocumulus IFO program. A wide variety of instruments will be carried on the various aircraft, which will fly at levers ranging from the surface layer to the longer stratosphere. The key observational capabilities of the aircraft can be summarized as follows:

Two turbulence aircraft that are most likely to be available for FIRE's stratocumulus segment are the NOAA/OAO WP-3D and the NC AR King Air. The P3 is described in Appendix C, and the King Air is discussed in Appendix E. Each aircraft is equipped with a nose-boom-mounted gust probe system for turbulence measurements, as well as a wide variety of other sensors, including cloud microphysics and radiation instruments, that will complement both the groundbased and satellite observations. They will be used in FIRE to make cross-wind and along-wind measurements in the vicinity of SNI in cooperation with the "round and satellite work.

Fast-response fluctuations in velocity components, temperature, and humidity can be measured with sufficient accuracy that vertical fluxes of these variables can be estimated throughout the CTBL including the entrainment zone. Following the methods of Lenschow et al. (1982), measurements of the ozone flux and mean concentration profiles through the boundary layer and its capping inversion will be used to estimate the entrainment velocity at the top of the boundary layer. Humidity fluctuations will be measured from aircraft by ultraviolet absorption (the Lyman-alpha fine) and microwave refractometry.

Measurement of divergence in the marine boundary layer by integrating the mean horizontal wind field around a closed flight path may not be feasible because of time changes that can occur during the flight (Brost et aI., 1982a). Possibly this problem can be solved by using several aircraft simultaneously. Alternatively, by invoking the PBL mass budget, the vertically averaged PBL divergence can be estimated from the entrainment velocity and the time rate of change of the PBL depth.

A downward pointing lidar and a multispectral cloud radiometer will fly on the NASA ER-2 in the longer stratosphere, for the purpose of mapping the structure of the cloud-top surface. This will provide high-resolution data on the entrainment process at the cloud top, and will also give quantitative information about the small scale structures of in-cloud turbulent elements. It will be particularly useful in cases where the cloud is in the process of breaking apart. The ER-2 will also be instrumented with a multispectral cloud radiometer, to measure cloud optical and radiative properties, and a thematic mapper simulator that mimics the AVHRR satellite instrument. ER-2 flights will be coordinated with coincident flights by the University of Washington C-131A cloud/ aerosol research aircraft that will provide the necessary in situ measurements to allow the cloud microphysics and radiative properties to be related.

The principal instruments on the ER-2 are the Multispectral Cloud Radiometer (MCR), Cloud Lidar System (CLS), and modified version of the Thematic Mapper Simulator (TMS) radiometer to provide high resolution measurements at AVHRR wavelengths. (A brief description of these instruments is given in Appendix A.) An important application for the high altitude aircraft experiment is to provide "ground truth" for satellite derivations of cloud fraction and cloud top altitude. Specifically, the aircraft observations will be compared with satellite AVHRR observations. A second application is to provide simultaneous multi-angle radiance observations for radiative model tests using the aircraft and satellite data (e.g. LANDSAT/5 TM and TMS simulator).

Even though marine stratocumulus clouds occur at low levels, observations with the high altitude aircraft will be extremely useful. A high altitude aircraft will be needed to provide an adequate swath width for the scanning radiometers. The capabilities of the ER-2 platform will permit full coverage of a 200-by-200 km area in a 3-hour period by the onboard scanning radiometers. Within the sampled area, the TMS will provide observations at 50 m or greater resolution at the simulated AVHRR wavelengths, and the lidar measurements will give extensive coverage of the height structure of the cloud systems. Moreover, the presence of cirrus clouds, which are expected to very frequently overlie the CTBL, can be detected and quantified by downward observations from the high altitude aircraft.

ER-2 lidar studies will concentrate on deriving the cloud-top altitude and cloud morphology of maritime stratus and stratocumulus clouds, as well as the spatial distribution of cloud optical thickness. Two current problems of particular interest are the "cloud absorption paradox" and the "cloud optical depth paradox" discussed in Section 3.22. To address these two problems in situations where the surface albedo and the fractal structure of clouds are the least troublesome, a full complement of measurements will be obtained during episodes of thick and horizontally extensive coastal stratus or stratocumulus cloudiness.

In order to accomplish these objectives, the ER-2 flights will be coordinated with in situ cloud microphysics and cloud radiation observations made by the University of Washington's C-131A cloud and aerosol research aircraft, as well as the other FIRE research aircraft. The C-131A will provide information on the cloud particle size distribution, thermodynamic phase and liquid water and ice water contents . Through a combination of these data, the cloud-radiometer-derived optical thickness will be compared to that predicted from the cloud microphysics observations. These data will help to address the relationship between the effective optical depth of a cloud for radiative transfer purposes, and the optical depth predicted from the integration of the measured liquid water content and effective particle size.

In addition to cloud microphysics observations, the University of Washington C-131A includes a multichannel scanning radiometer designed to derive the spectral single scattering albedo of clouds. The concept behind the cloud absorption measurements is the diffusion domain method described by King (1981). (A brief description of the Cloud Absorption Radiometer and the cloud microphysics measurement capabilities of the UW C-131A are given in Appendix B.)

Upward and downward pointing lidar systems will be flown on NASA 's CV-990. The aircraft will also carry a PRT-5 radiometer (looking clown), a 70 mm camera, a Rosemount 102 air temperature sensor, and a General Eastern 1011 dew/frost point hygrometer. The measurements will be coordinated with data from GOES and LANDSAT, as well as other aircraft data. Plans call for three 4-hour flights per day, to allow good sampling of diurnal variability.

Narrowband measurements, made with a minimum number of instruments (to minimize intercalibration problems) will also fly on the CV-990, as will a sun- tracking photometer (which can give important values of cloud optical depth) and a PMS system. Much of this equipment has been flown on a P-3, and the possibility of combining the systems is being explored.

A description of the instruments to be flown on the CV-990 is given in Appendix D.

Finally, a small, highly maneuverable Queen Air aircraft, operated by the NOSC in San Diego, will make aerosol and meteorological measurements in the profiling mode, to provide high-resolution aerosol concentration observations and vertical profiles of boundary-layer variables.

Table 5 summarizes the aircraft observations.

. .

The measurement of cloud liquid water and water vapor is an important part of the envisioned measurement program. Liquid water mixing ratios will be inferred from the radar reflectivity factor; in situ measurements of liquid water content and droplet spectra will also be made to infer the relationship between liquid water and reflectivity. Ground-based scanning dual - channel microwave radiometers will be used to continuously monitor the temporal and spatial variability of total liquid water and water vapor overhead, for comparison with satellite-observed cloud reflectivity.

A Doppler radar will provide information about the turbulent kinematics of the cloud layer, including profiles of horizontal and vertical wind components, convergence, and the turbulent fluxes of momentum within the cloud layer. Such profiles are generated from cortical scan data (Browning and Wexler, 1968). The elevation angle chosen for such a scan depends on the quantity to be measured; low elevation (<15¡) are best for convergence measurements, an elevation angle of 45¡ minimizes the error in measuring the vertical flux of momentum, and near vertical elevations optimize the measurement of vertical velocity and its variance. Horizontal wind profiles can be measured with good accuracy at elevation angles below 75¡.

Similar velocity measurement techniques will be applied below cloud base and several hundred meters into the cloud by means of pulsed infrared Doppler lidar, which uses atmospheric aerosols for scatterers (Hall et al., 1984). Instruments currently being tested have an effective range of 20 km or more in the subcloud layer of the CTBL. Such systems, operating in the cortical scan mode, have already demonstrated their ability to observe wind profiles and turbulence in the dry planetary boundary layer.

It is anticipated that a Doppler radar and a Doppler lidar will be operated at SNI each day for 5 hours during the afternoon, and again for 5 hours after midnight. A sequence of 4 or 5 RHI scans at various azimuths will be followed by a sequence of 4 or 5 PPI scans at various elevation angles ranging from ~10¡ to 90¡. The 90¡ scan will allow measurement of the vertical motion field at cloud-top. These, combined with measurements of the actual lime-rate-of-change of cloud-top height, would allow determination of the entrainment rate. This strategy will be tested using data collected prior to FIRE.

An array of ground-based remote sensors at SNI will document various aspects of the cloud dynamics and microphysics. Particle sizes and shapes will be probed using a dual-polarization lidar system, and simultaneous measurements of surface infrared and solar radiation will provide a means of relating these particle spectra to cloud radiative properties. The cloud LWC will be monitored by a dual-charnel microwave radimeter; this data will be compared with LWC observations from the satellite platform. The cloud microphysical data will be complemented by tower measurements (using a PMS system) of subcloud aerosols.

Two candidate tethered balloon systems are planned for use in the FIRE Stratocumulus Subprogram. The first has been developed for the U.S. Navy by a private contractor (LTA International), and was flown in 1984 by NRL at SNI. It is 17 m long, has a volume of 220 m³, and under conditions of zero wind can lift a payload of approximately 20 kg to an altitude of 1 km. It is capable of operating in flight-altitude winds of 20 m s^-1. A cloud physics instrument package (including temperatures and winds) has been developed by NRL for use with the balloon.

The second, significantly larger candidate tethered balloon has been developed by the Wallops Flight Facility of the NASA/Goddard Space Flight Center. It is portable, and has flown at various sites including Virginia and Alaska. It is 31.6 m long, has a volume of 1275 m³, and under zero-wind conditions can lift a payload of approximately 400 kg to an altitude of 1 km. It is capable of operating in flight-altitude winds exceeding 25 m s^-1. This balloon is large enough to lift the comprehensive instrument package developed by the British Meteorological Office (Slingo et al., 1982; Caughey et al., 1982; and Roach et al., 1982, Caughey and Kitchen, 1984). This package consists of an optical scattering droplet spectrometer (ASSP), two CSIRO net radiometers, a turbulence probe, a microwave radiometer to measure integrated liquid water content, and a pressure sensor for height measurement. These instruments are strung along a cable 40-50 m below the balloon. The instrument package includes its own telemetry system. The balloon can remain aloft for up to 72 consecutive hours, after which the batteries must be changed. It will be used both at fixed levers and to make soundings.

Both tethered balloons can be deployed on SNI and operated at different levers or in different modes (e.g. sounding mode vs. constant lever mode) to investigate the vertical coupling of various boundary layer processes. Alternatively they can be deployed at different locations (e.g. San Nicolas and San Clemente Islands) to gain additional information about the role of horizontal advective processes.

In addition to broadband net radiation measurements at the surface, a three spectral bandpass scanning radiometer will be used to measure sky and "round radiance in the visible and near infrared wavelengths.

A summary of surface observations appears in Table 1, Section 4.222.

i. Cirrus Working Group

ii. Marine Stratocumulus Working Group.

It is clear that physical process modeling, which includes all processes important to the maintenance and to the characterization of cloud systems, and large scale GCM and climate modeling are critical to the successful attainment of FIRE's goals; it is extremely important that these modeling components be integrated with the observational components of FIRE. For this reason, FIRE investigators with modeling interests will play important roles in both the cirrus and stratocumulus working groups.

The cirrus and marine stratocumulus working groups will accept the following responsibilities:

Since some data sets will be common to both working groups, a single principal investigator may be expected to participate actively in both groups; this presents a potential problem of over commitment. To partially alleviate this problem some resources should be set aside to support postdoctoral associates to work with overcommitted principal investigators.

All deliberations of the Miss ion Selection Team will be open and in the lack of a clear consensus among its members, the chairman will assume responsibility for making operations decisions.

On issues concerning specific platforms such as aircraft or special rawinsonde accents, an appropriate spokesperson from the contributing organization will be given the opportunity to advise the MST and to participate on the MPT.

A Mission Planning Team (MPT) will be active during the cirrus and marine stratocumulus Intensive Field Observation Phases. The Mission Planning Team will contain at least three FSET members, individuals representing participating aircraft facilities and FIRE Project Office support personnel. The MPT members for the following day will be identified on a daily basis by the MST. Ideally, on any given day, the MPT will contain candidate mission scientists for the following day's operations. It will not be uncommon for members of the MST to also serve as members of the MPT. The MPT's responsibilities are listed below.

A Mission Scientist must have an overall grasp of the scientific objectives of FIRE as well as an appreciation of operational constraints of the various platforms and personnel.

Data management activities in FIRE will insure the exchange of data among FIRE investigators that is required to produce the integrated analyses of multi-platform, multi-scale and mufti-spectral data sets; these integrated analyses are central to the accomplishment of the FIRE science objectives. In addition the data management activities will insure the availability of FIRE data and analysis products to the entire science community. These activities will be carried out by four organizational components within FIRE: (1) the individual FIRE investigators, (2) the FIRE Working Groups, (3) the FIRE Central Archive, and (4) the FIRE Project Office. The strategy embodied in this organization is to disperse most of the data reduction and processing functions to the FIRE investigators engaged in collecting and analyzing the data, but to hold the resultant data sets and analysis products centrally for ready access by all FIRE investigators. The FIRE Central Archive and the FIRE Project Office will provide a centralized source of information and copies of data which are centrally archived, whereas the FIRE Working Groups, composed of the investigators, will coordinate the decentralized data reduction and analysis activities. In addition, the FIRE Central Archive will transfer, from time to time, certified FIRE data to EDIS and/or other organizations for permanent archive and for open access by the scientific community.

There are two FIRE Working Groups - a Cirrus Working Group and a Marine Stratocumulus Working Group (see section 6.1). These working groups will be composed of FIRE principal investigators pursuing research relevant to that working group. The data management responsibilities of the individual principal investigators, as dispersed elements of the FIRE data processing system, could become onerous if not coordinated properly, so the FIRE Working Groups must govern these individual activities to insure progress toward the FIRE science objectives. The data management functions of the two FIRE Working Groups are:

The estimated data volumes for the different FIRE data acquisition activities are given below as a number of 6250 bpi density data tapes per year:

IFP (assumes one IFP per year) 280

ETO-LA (four regions) 300

ETO-EA 20

The complete ETO-EA data set will reside in the ISCCP archive currently being acquired and maintained by NOAA. Only specific subsets of the NOAA archive will be transferred to the FIRE Central Archive as the specific needs and priorities of FIRE are identified by FIRE investigators and working groups. The twenty tape per year entry in the above table represents the estimated volume of the subsets to be acquired by the FIRE Central Archive and is less than one-twentieth of the total ETO-EA data volume which will reside in the ISCCP archive.

Each of the data acquisition activities is important to achieving the goals of FIRE; however, resource planning and the natural chronological sequence of tasks in pursuing a scientific investigation dictate the need for some relative prioritization of these tasks. The data acquisition activities and the relative priorities assigned to each by the FIRE Science Experiment Team are listed below.

Although many factors were considered in the assignment of the above priorities, the overriding considerations are summarized below.

The Cirrus (Ci) Intensive Field Observations, Phase I was given the highest priority because relatively little previous work has been reported on this climatologically important cloud system; a lack of observations of Ci is often cited as the reason for the embryonic state of research on cirrus cloud systems. As a result there is much to be learned and much to be gained from this initial set of observations and subsequent studies. This same argument also applies to the Extended Time-Limited Area observations of both cirrus and stratocumulus systems.

The Stratocumulus (Sc) Intensive Field Observations, Phase I was given the second highest priority. Substantial progress in making Sc observations and in modeling Sc systems has allowed researchers to formulate very specific questions designed to elucidate the behavior of these systems. These observations will fill gaps in previous observational programs and address specific questions to promote an effective GCM parameterization of this phenomenon.

The Ci Intensive Field Observations, Phase II was given the third highest priority. Because of the primitive state of our understanding of Ci cloud systems,-a two stage Ci observation program is essential. Phase II will be designed around what is learned from the Phase I observations and subsequent model developments. The Phase II program will possibly shift its focus to more complex cirrus cloud systems and to a geographical region different from that of Cirrus, Phase I studies.

The Extended Time - Extended Area observations were given the fourth highest priority. This priority was assigned based on the fact that the data are being archived routinely by U. S. government agencies. Therefore, these data may be accessed from these independent archives at a later time. This is not meant to imply that the ET-EA data set is expendable; it is not. It should be noted that a substantial satellite data archive will be accumulated in the Priority 1 activity, Extended Time - Limited Area observation data set.

The fifth priority was assigned to the Sc Intensive Field Observations, Phase II. While there will undoubtedly be much to gain by conducting these observations, the FSET assigned higher relative priorities to other components to bring about a parity in the understanding of cirrus and stratocumulus cloud systems and in their parameterizations.

The FSET emphasizes that all FIRE observational components are important to the attainment of FIRE goals. Means of acquiring the resources for all components of FIRE must be actively pursued. The priorities assigned above are offered only in the context of assisting the formulation of a plan to accomplish all of FIRE's goals.

DESCRIPTION OF NASA ER-2 INSTRUMENTS

1. Cloud Lidar System (See also Section 5.151)

A unique element of the proposed radiation investigation is a lidar instrument which provided absolute range resolved measurements to complement passive observations. The lidar system operated at dual wavelengths and dual polarization. Backscattered return signals are digitized with a 7.S m vertical range resolution and, at the nominal pule repetition rate of 3.47 Hz, a return signal is acquired every 50 m of horizontal distance. The system characteristics are summarized in Table A.1. The lidar system has been flown on the NASA WB-57F aircraft and is currently integrated to and operational from the NASA ER-2 aircraft. The lidar system is mounted in the forward section of an ER-2 superpod which also contains the Multispectral Cloud Radiometer (MCR). Support systems for both instruments include the data system and tape recorder, mounting facilities, power system, and navigation and timing information. The co-location in a single pod permits a direct optical alignment and time synchronization between the lidar measurements and the cloud radiometer nadir pixels. A full description of the CIS is given by Spinhirne et al. (1982). Representative results from an earlier field program are described by Spinhirne et al. (1983).

2. Multispectral Cloud Radiometer

The Multispectral Cloud Radiometer is a seven-channel scanning radiometer whose spectral characteristics are summarized in Table A.2. The spectral charnels were specifically selected from remote sensing of cloud properties. The instrument was designed so that it scans through nadir in a plane perpendicular to the velocity vector of the aircraft, where the scan extends up to 45¡ on either side of nadir. All channels are sampled simultaneously in order to permit a high degree of registration among wavelengths.

Table A.1. ER-2 LIDAR SYSTEM CHARACTERISTICS

The optical system of the cloud radiometer is of the non-dispersive filter-dichroic configuration. The optical path consists of a 12.38 by 17.5 cm scan mirror, canted 45¡ to the long axis of the instrument; a 12.38 cm Dall-Kirkham (Cassegrainian) telescope; ant a complex configuration of dichroic filters, mirrors, lenses, filters and a single prism. The instantaneous field of view of the radiometer is 7 mrad, resulting in a "round resolution at nadir of 133 m. A more complete description of the MCR is given by Curran et al. (1983).

Central Central Spectral

Channel wavenumber wavenumber resolution Principal Function

number (cm-l) (Um) (Um)

1 13271 0.75350 0.00108 Optical thickness

2 13146 0.76070 0.00121 O₂ A-band altimetry, volume

scattering coefficient

3 13099 0.76339 0.00112 O₂ A-band altimetry, volume

scattering coefficient

4 6093 1.6412 0.0641 Cloud phase, particle size

5 5836 1.7136 0.0457 Cloud phase, particle size

6 4630 2.1599 0.0894 Cloud phase, particle size

7 932 10.73 0.90 Temperature

3. Thematic Mapper Simulator

The Thematic Mapper Simulator is a multispectral scanner which may be flown in the Q-bay of the ER-2 aircraft, and which simulates the spatial and spectral characteristics of the Landsat-4 Thematic Mapper bands. The Advanced Microwave Moisture Sounder (AMMS), which has flown in the peat in the aircraft Q-bay, is not being proposed as part of the present study. The U-2 modified TMS will be the Q-bay instrument for our study. This version of the TMS is available with a 11 µm split window charnel and a 6.7 µm charnel. For the proposed experiment, the 6.7 µm charnel will be replaced with a 3.7 µm charnel. The TMS will then serve the function of a high resolution imager with bands similar to the AVHRR satellite instrument. The characteristics of the TMS as configured for the experiment are listed in Table A.3.

DESCRIPTION OF UW C131-A INSTRUMENTS

1. The Cloud Absorption Radiometer

The Cloud Absorption Radiometer (CAR) is a thirteen-channel scanning radiometer whose spectral characteristics are summarized in Table B. l. All of the wavelengths were selected to avoid the molecular absorption bands, so that the anticipated absorption would be due solely to water or ice particles and aerosol particles. The instrument scans in a vertical plane from 5¡ before zenith to 5¡ peat nadir (190¡ aperture). This permits observations of the internal scattered radiation field within clouds in both zenith and nadir directions with as much as a 5¡ aircraft roll.

The optical system of the CAR is of the non-dispersive, filter dichroic configuration (Fig. 4). The optical path consists of a 12.4 by 17.5 cm scan mirror, canted 45¡ to the long axis of the instrument, a 12.4 cm Dall-Kirkham (Cassegrainian) telescope, and a complex configuration of dichroic filters, collimating lenses, mirrors, beam splitters, filters and a filter wheel. The filter wheel contains optical charnels 8 through 13. Every fourth scan the filter wheel rotates to measure a new wavelength interval. With this configuration the first seven channels are continuously and simultaneously sampled, while the eighth registered charnel is selected from among the six charnels on the filter wheel. The instantaneous field of view of the radiometer is 1¡ (17.5 mrad). A more complete description of the instrument as well as initial observations are given by King et al. (1985).

2. The University of Washington's Airborne Research Facility

For the past fourteen years the UW has utilized a B-23 aircraft for cloud and aerosol research. The CAR was integrated into this facility in 1983, and it was aboard this aircraft that the CAR was flight-tested and the first measurements with the CAR were obtained.

The B-23 has recently been replaced by a Convair-131A. This aircraft is now being equipped for clout ant aerosol research and the CAR is being mounted onto it. The instrumentation on the C-131A can be sub-divided into the following broad categories: navigational and flight characteristics, meteorological (including radiation), cloud physics, aerosol, cloud and atmospheric chemistry and data processing and display.

(a) Aerosol

Aerosol in the size range of 0.01-45 µm are measured using several instruments that are all fed from a common batch sampler of air aboard the aircraft. The batch sampler consists of a stainless steel cylinder 90 liter in volume and 1.5 m high which has a freely-floating piston. Electric valves control the filling and emptying of ambient air samples into and from this cylinder. Ram air pressure forces the piston upwards, filling the cylinder with ambient air ant closing the air inlet valve. Since the piston offers negligible resistance to the in-rushing air (the pressure above the piston is reduced), sampling of particles is close to isokinetic.

After the cylinder is full, air from its base pesses into the various instruments. The instruments size the particles after any water on them has been evaporated by passage through a diffusion drier. Hence, these instruments provide the dry size spectra of particles from 0.01 to 11 µm. The Royco 245, on the other hand, measures particles in the size range 2 to 45 µm without any significant drying.

When such measurements are made in clouds, the particles that enter the diffusion drier, and are subsequently sized, are primarily cloud interstitial aerosol. This is because the cloud drops are removed by a cyclone which is switched into the first bend in the air inlet sampling tube for interstitial sampling. (The large bag sampler employed for filter sampling, on the other hand, removes cloud droplets greater than ~5 µm radius via impaction.)

This system has been successfully used to measure cloud interstitial aerosol for several years (Radke, 1983).

(b) Cloud physics

The critical questions which the cloud physics instrumentation must resolve are 1) what is the liquid water content (LWC) and droplet size distribution and 2) does the cloud include hydrometeors and, if BO, in what phase?

We measure the LWC by three independent techniques, The Johnson-Williams (J-W) hot wire, a new King/CSIRO hot wire and a PMS FSSP. The FSSP gives the droplet size distribution and the LWC is calculated. The FSSP and J-W values of LWC have historically been in excellent agreement. We have had no flight experience with the King probe, but it is believed to have even less drift and error than the J-W.

The nature of the hydrometeors and the concentrations of ice are determine from the 1-D and 2-D PMS Cloud (C) and precipitation (P) probes and the UW ice particle counter. These five probes provide both automatic and visual confirmation of the presence of ice particles and hydrometeors. The OAP-2D C and P probes provide visual identification of crystal habit and some indication of crystal riming.

The aircraft is also equipped with bulk cloud water samplers. We intend to filter the cloud water and analyze the filter optically, as described by Clarke (1982), as another approach to examining the cloud's optical absorption characteristics.

DESCRIPTION OF NO M WP-3D ORION INSTRUMENTATION

The Lockheed WP-3D Orion (hereafter, the "P3") is a long-range turboprop aircraft, originally developed for Naval submarine surveillance work, that has been equipped by NOAA/0AO for meteorological research. As configured for the Stratocumulus Subprogram of FIRE, the P3 will cruise (et high altitude for ferrys) at ~350 knots; the nominal operating speed for boundary-layer turbulence work is 200 knots (100 m s^-1) ± 10%. Depending on load factors and altitude, the P3 can remain aloft for about 9 hours for a maximum-range mission. The instruments to be used in FIRE, listed below, will allow 8-10 scientists, plus the NOAA/OAO crew, to participate. The instrumentation is moat conveniently grouped by response time.

1. Standard Flight Instruments (1 Hz sampling)

The main flight data recording computer records standard flight variables and some custom instruments at 1 sample per second. These are given in fable C.1. In addition, several other derived variables (for example, potential temperature, water vapor mixing ratio and air density) are calculated and recorded. [Some post-flight data reduction is necessary to convert the radiometric observations to SI units, and post-flight calibration corrections are sometimes necessary.] A ten-hour mission can generally be reduced to one 9-track high-density tape.

2. Gust probe instruments (nominal 20 Hz sampling)

The noseboom mounted gust-probe turbulence system is maintained by NOAA/ ERL/ESG, and contracted to OAO by individual investigators. The gust probe instruments include vanes to sense the three wind components, a bead thermistor for temperature fluctuations, and a microwave refractometer for humidity. The INS is also used, at a longer sampling rate, to stabilize the wind measurement. The gust-probe sensors are sampled first at 80 Hz, then averaged and processed to 20 Hz, producing a nominal spatial resolution of 5 m. The data are reduced to standard nine-track tape format at NOAA/ERC/ESG. The data volume depends on the amount of time during a mission during which the gust probe is "on"; for some missions three high-density tapes have been produced.

3. Knollenberg PMS

The fastest-responding instruments on the P3 are contained in the cloud microphysics package, consisting of FSSP and 2-D systems from PMS. This system has a dedicated recording system that operates only when the system encounters cloud drops large enough to sense. This is a standard PMS system described extensively elsewhere.

4. Miscellaneous

The P3 also has Omega dropwindsonde (ODW) and airborne expendable bathythermograph (AXBT) capability. ODW data are recorded on a separate (cassette) recorder and processed by NOAA/ERL/HRD in Miami, and the AXBT data is recorded by the main flight computer. Three AXBT‘s can be recorded simultaneously.

In addition to the radar and flight radars, the P3 can be equipped with a Doppler radar (for rainfall data) with a dedicated computer.

DESCRIPTION OF NASA CV-990 INSTRUMENTS

(See also Section 5.152)

1. Airborne Lidar System

The CV-990 will carry a lidar system composed of two independent lidars, a ruby laser (l = 0.6943 µm), and a ND: YAG laser (l 1.06 µm) One laser is uplooking (zenith) while the other is downlooking (nadir). The lasers are interchangeable, so that either can be used on the uplooking or downlooking mode. In addition, their second harmonic (doubled frequency) can be used simultaneously making each a two-wavelength lidar. Each lidar has its own computer-driver data acquisition system, capable of handling two-wavelength or two-polarization data. Real-time profile and intensity modulated diaplays are available, to assist decision--making in the field. The lidar measurements will provide cloud top height, cloud thickness (for optical depths leas than about 3, such as over-lying cirrus), and cloud optical depth for thin clouds.

2. Flux sensors

The CV-990 will also carry a newly developed 2p sr flux sensor for longwave radiative flux density measurements. This instrument, to be mounted on the wing tip of the aircraft, will be able to be rapidly flipped between an uplooking and downlooking mode such that net infrared flux measurements can be made above the clouds with a single instrument. This instrument has not yet been constructed. In addition, 2 shortwave flat plate flux sensors will be mounted on the fuselage one in an uplooking mode and one in a down-looking mode. A nadir-viewing PRT-5 infrared radiometer (9.5-11.5 µm) will d so be flown.

3. Spectral Scanning Radiometer

Either one of two possible spectrally scanning radiometers will be flown

on the CV-990. One of these radiometers, developed at CSIRO, was recently flow on the CSIRO Focker Friendship aircraft. It i6 a nadir-viewing instrument with circular variable filter capable of rapidly scanning in wavelength from 0.5t2.3 um in order to provide a detailed spectra of reflected radiation. It could be modified to look upward as well. The other possible instrument is an Israeli instrument recently acquired by CSU. It scans in a vertical plane from zenith to nadir and also contains a circular variable filter. It is capable of observing spectral radiance from .35 to 20 µm using modular detectors. Neither of these instruments has previously been integrated on the CV-990.

4. Bugeye Radiometer

This instrument is a multi-angle fixed field of view instrument which measures the reflected intensity (radiance) in 1 wavelength band (0.3-0.9 µm). This instrument has flown during MONEX.

5. Sunphotometer

The CV-990 ,has recently flown with a sunphotometer capable of measuring the spectral optical depth of aerosols and thin cirrus clouds above the aircraft. The sunphotometer is mounted externally to the airframe and has automatic suntracking capability.

6. Ancillary data

The CV-990 also carries a 70 mm camera, a Rosemont 102 air-temperature probe, and a General Eastern 1011 dew/frost point hygrometer.

DESCRIPTION OF NCAR KING AIR INSTRUMENTATION

The NCAR Ring Air is a twin-engine turboprop aircraft. It can remain aloft for 4-5 hours at 75 m sec^-l. Its range with full fuel ant optimum altitude is 3300 km. It carries the instruments listed in Table E.1. Further information is given by Phillips and Friesen (1984).

SURFACE MEASUREMENTS ON SAN NICOLAS ISLAND

1. Penn State Facilities

The Department of Meteorology of the Pennsylvania State University maintains for research use a comprehensive array of micrometeorology sensors, processing and logging systems suitable for complete energy budget or surface layer turbulence analysis. Radiation sensors and calibration standards are as follows:

a. Sensors

Precision Spectral Pyranometers

0.395-3 µm

0.695-3 µm

Pyranometers

2 each: Epply Model 8-48

Pyrgeometers

2 each: 4-60 µm

Si cell Radiometer

Li-Cor Pyranometer

Net Radiometers

2 each: Swissteco S-1

b. Standard

Linke-Ruessner Pyrheliometer

The department also has a system for combined wind-temperature-humidity profiling using remote sensors, and a dual charnel (20 and 30 GHz) water vapor/ liquid radiometer, and a six-channel (60 Hz) radiometer for temperature profiles. A water-vapor radiometer is planned for FY86 funds, and the system will be operational in FY87. The first major field deployment of the water-vapor system will be the FIRE project at SNI. This equipment will be used during the intensive phase only.

2. Naval Postgraduate School Facilities

METEOROLOGICAL MEASUREMENTS/OBSERVATION

Frequency of

Radiation (down Long/short wave Continuous

and reflected) radiometers

Sea Surface Temp- Floating thermister Continuous

erature

Mean surface layer:

Wind (speed, Cup anemometer Continuous

direction) vane

Temperature Resistance thermo- Continuous

meter

Humidity Dew cell Continuous

(cool mirror)

Aerosols* Optical Counters Continuous

(.3 to 300)

Turbulent Kinetic* Hot film/ Continuous

Energy Dissipation Miniature Cups

Rate

Inversion Height, Doppler Sodar Continuous

Turbulence

Temperature, Humidity, Buekers 2 to 8/day

and Wind Profiles* Radiosonde

Sky and Sea* Visual observations Hourly

Conditions

* Primarily for intensive data periods

NOAA/WPL Ground-Based Remote Sensors

During FIRE IFO's, ground-based sensor systems will play an important role in obtaining both in situ and remote measurements for satellite comparison and validation as well as for completing the physical picture of meteorological conditions that occur. The second role applies especially to the NOAA/ERL/Wave Propagation Laboratory's ground-based remote sensor systems. These are described briefly in the following sections. The first three systems are described in more detail in the May, 1983 issue of Journal of Climate and Applied Meteorology in articles by Pasqualucci et al., Hogg et al. (p.789) and Hogg et al. (p. 807), respectively, and the lidar system capabilities are described fully in articles by Hall et al. and Post et al. in the 1 August 1984 issue of Applied Optics.

i) K_a -band Doppler radar.

Operating at a somewhat shorter wavelength than conventional meteorological radars allows the Ka -band radar to detect the presence of particles smaller than raindrops. Although this causes strong attenuation in the presence of heavy precipitation, motions in non-precipitating clouds can be observed by the detection of large-non-precipitating cloud droplets. This will be a valuable (and in fact the only) tool during the FIRE stratocumulus IFO's for observing mesoscale divergence fields.

Table G-1

Description of NOAA/WPL Ka-band radar

The following table summarizes the operating characteristics of the WPL

K_a -band Doppler radar:

wavelength 8.66 mm (35 GHz)

peak power 100.00 KW

pulse duration .30 µs

average power 50.00 w

antenna diameter 1.2 m

system gain 48.00 dB

beamwidth 0.5 deg.

minimum detectable reflectivity at 10 km -26.00 dBz

The computer controlled antenna can rotate continuously in azimuth at fixed elevation (PPI mode) to provide continuous profiles of the three wind components, turbulent fluxes and variances, and the height of the echo top. It can also scan in elevation through the zenith at fixed azimuth (RHI mode) to provide a vertical cross-section of the echo. A wide variety of other scan options is available. The radar has a dual charnel receiver for measurements of linear or circuler depolarization ratio. The minimum range for reliable velocity measurements is about 200 m and the maximum range is adjustable by controlling the radar pulsing sequence. Nominal vertical resolution can be as small as 40 m. A puise-pair algorithm has been implemented in a real time digital processor which removes the DC spectral fine for partial "round clutter suppression. Other modes of operation allow time-series data to be recorded for off-line spectral processing.

ii) Steerable Microwave Radiometer

The two-channel microwave radiometer is designed to sense remotely the integrated amounts of liquid water and water vapor in the atmospheric column (either vertical or slant patin). This instrument will be used during the stratocumulus IFO's to provide time series estimates of cloua water and atmospheric water vapor. Steerability allows slant-path measurements to be made. Essential characteristics are listed in Table G-2.

Table G-2

Microwave Radiometer Characteristics

Radiometer 1 Radiometer 2

Center wavelength 14.7 mm (20.6 GHz) 9.59 mm (31.6 GHz)

Bandwidth 1.O GHz 1.O GHz

Receiver Noise Temp. 680° K 725° K

Sensitivity 0.26° K 0.26° K

The system can operate in three modes: 1) fixed azimuth and elevation angles; 2) continuous 360 degree azimuth scans at fixed elevations; and 3) variable azimuth and elevation scans. The sampling rate for each mode is 10 Hz and averaging times are ten seconds for mode 1 and one second for modes 2 and 3.

iii) VHF Doppler Radar

Large aperature (for sensivity) radar systems of appropriate wavelength are capable of detecting backscatter from atmospheric turbulence in optically clear air. The WPL 6-m (VHF) Doppler system is designed to provide vertical profiles of the three-di'mensional wind vector. This instrument will be an important comportent of the cirrus IFO's for vertical motion studies. Combined with the lidar system (below), it will enable mapping of the relationships between cloud-scale and large-scale motions. The VHF radar characteristics are given in Table G-3.

Table G-3

VHF Radar Characteristics

Wavelength 6.o m (49.9 MHz)

Pulse Width 16.0 µs

Pulse Repetition Period 2.4 ms

Peak Power 10.0 kW

Range Spacing 1500 m (10 ps)

Levels Observed 13

Minimum Range ~2 km above ground

The radar's capability for vertical wind measurements would be augmented considerably by an array of three (or more) radars. Using such an arrangement, area- and time-averaged divergences coula be compared with point measurements. It is worth remarking here that the NOAA/WPL wind profiles is one comportent of a complete profiler system that also obtains temperature and humidity profiles. These are also described in the second of the articles by Hogg et al. -

iv) IR Doppler Lidar

The 10.6 pm pulsed infrared Doppler lidar system is capable of detecting atmospheric aerosols, winds and cirrus cloua particles. Recently the system's capabilities have been upgraded to include dual polarization sensitivity. Since cirrus ice particles are frequently transparent to solar radiation, the IR lidar is an important part of the cirrus program. System characteristics are listed in Table G-4.

Table G-4

IR Doppler Lidar Characteristics

Wavelength 10.6 µm

Power per Pulse 0.25 J

Pulse Repetition Rate 1 - 100 Hzµ

Pulse Duration 1 - 4 us

Trans./Recv. Telescope 0.25 m Aperture (off axis)

Scan Capability Alt-Azimuth

Minimum Range 0.5 km

Maximum Range 20+ km

Depending on the pulse repetition rate, the ranging can be as small as about 200 m. The potential for polarization studies has great significance for FIRE as it will give information about cirrus particle shapes and/or orientation.

GLOSSARY OF ACRONYMS

AVHRR Advanced Very High Resolution Radiometer

CTBL Cloud-Topped Boundary Layer

EDIS Environmental Data Information Service

ERBE Earth Radiation Budget Experiment

ERBS Earth Radiation Budget System

ETO Extended Time Observations

ETO-EA Extended Time Observations - Extended Area

ETO-LA Extended Time Observations - Limited Area

FIRE First ISCCP Regional Experiment

FSET FIRE Science Experiment Team

GAC Global Area Coverage

GCM General Circulation Model

GOES Geostationary Operational Environmental Satellite

HIRS High Resolution Infrared Sounder

IFO Intensive Field Observations

ISCCP International Satellite Cloud Climatology Project

LAC Local Area Coverage

LANDSAT TM LANDSAT Thematic Mapper

NASA National Aeronautics and Space Administration

NESDIS National Environmental Satellite Data and Information

Service

NMC National Meteorological Center

NOAA National Oceanic and Atmospheric Administration

NOAA/OAO NOAA/Office of Aircraft Operations

NRL Naval Research Laboratory

NWS National Weather Service

PROFS Prototype Regional Observing and Forecasting Service

PMS Particle Measuring Systems, Inc.

SAGE Stratospheric Aerosol and Gas Experiment

SNI San Nicolas Island

TOVS TIROS Operational Vertical Sounder

VAS Vertical Atmospheric Sounder

WPL Wave Propagation Laboratory

Schedule of Significant FIRE EVENTS

1 June, 1985 Submit FIRE Implementation Plan

1 September, 1985 Form Initial Task Groups

1 November, 1985 Complete Cirrus Observations Plan

Complete Extended Time

Observations Plan

1 January, 1986 Begin Extended Time Observations

1 June, 1986 Complete Marine Stratocumulus

Observations Plan

1 November, 1986 Cirrus Intensive Field Observations

1 January, 1987 Fort Collins, CO FSET REVIEW MEETING

1 June, 1987 Marine Stratocumulus Intensive

Field Observations

1 January, 1988 Hampton, VA FSET REVIEW MEETING

1 March, 1988 Cirrus Intensive Field Observations

1 January, 1989 Washington, D. C. FSET REVIEW MEETING

1 June, 1989 Marine Stratocumulus Intensive

Field Observations

1 January, 1990 Washington, D. C. FSET REVIEW MEETING

In addition, each field mission will have planning meetings approximately twelve months and six months before each mission, a preliminary data workshop three months after each mission, and a review of results nine months after each mission. These meetings will be coordinated and combined as much as possible with other mission activities. For example, preliminary estimates indicate that all mission planning/reviews, field missions, and FSET reviews can be consolidated into thirteen meetings over the next six years.