FIRE III Objectives/Methodology

The First ISCCP Regional Experiment (FIRE) has conducted basic research on climatically important cloud systems since 1984. FIRE was conceived as a national U.S. research program responding to the needs of ISCCP (International Satellite Cloud Climatology Project), an international World Meteorological Organization (WMO) program. Throughout its history, FIRE has been especially interested in the cloud - climate connection. As a result, integrated, interdisciplinary studies involving experimentalists, theoreticians, and modelers have been executed by the broad-based community of FIRE scientists. These specialists span the fields of radiation, cloud microphysics, and dynamics ranging from cloud-scale to the general circulation-scale.

Previous FIRE-I and FIRE-II research has centered on midlatitude cirrus cloud systems and subtropical marine boundary layer cloud systems. This research has enhanced our ability to both monitor these systems from satellites and to include their radiative effects in models of various scales. It has greatly increased our understanding of the control of these cloud systems by the large-scale circulation and has greatly enhanced our ability to realistically simulate these systems in GCMs. Modeling studies and field campaigns have greatly enhanced our understanding of these two climatically important cloud regimes. FIRE GCM research has added to our understanding of the importance of these cloud regimes in the climate system.

FIRE Phase III was initiated in 1995 as a follow on to FIRE-I (1984-1989) and FIRE-II (1989-1994). The First ISCCP (International Satellite Cloud Climatology Project ) Regional Experiment III (FIRE III) is a U.S. multi-agency research program designed to study climatically important cloud systems in the polar and tropical regions. FIRE-III has two primary components. FIRE will conduct an Arctic Cloud Experiment field campaign over the Beaufort Sea ice off the north coast of Alaska in spring 1998 to assess the role of arctic clouds in the high latitude climate system. FIRE may possibly conduct measurements of large-scale cirrus anvils associated with deep convection in the tropics in the year 2000. Clouds play important roles in the Earth's climate and postulated global warming. In fact, the inability to properly model clouds and their effects on climate is the largest source of uncertainty in general circulation model predictions of global warming.

A Boundary Layer/Arctic Cloud Component which consists of continuing investigations of subtropical marine stratocumulus systems and a new thrust aimed at Arctic cloud systems.

An Upper Tropospheric Cloud Component which consists of continuing investigations of middle latitude cirrus cloud systems with a methodical transition of emphasis to tropical upper-tropospheric cloud systems.

Specific research goals common to both the boundary layer/Arctic and upper tropospheric components of FIRE III are:

• Apply FIRE Phase I and II model and field campaign results to the improvement and evaluation of cloud-system parameterizations employed in large eddy simulation (LES) and global climate models (GCMs).
• Apply FIRE Phase I and II field campaign and theoretical results to develop and verify improved techniques for the inference of cloud radiative and microphysical properties from satellite and surface based data.
• Define the total water substance (vapor, liquid and ice) environment and transports associated with cloud systems.
• Define, design, test and implement measurement systems to observe key microphysical and radiative properties of cirrus and boundary layer clouds and cloud systems.
• Advance our understanding of climatically important cloud systems, the variability of their microphysical and radiative properties, the key processes involved in their formation and dissipation, and their roles in regulating the flow of energy between the surface and the atmosphere.
• Provide a methodical transition from FIRE Phases I and II accomplishments to a coherent research plan for the next generation of research on climatically important cloud systems.

The FIRE III Boundary Layer/Arctic Cloud Component will adopt the following strategies:

• The continued analysis of the wealth of observations obtained during the FIRE-I Marine Stratocumulus and FIRE-II ASTEX field campaigns and the FIRE extended time observations.
• The definition and execution of an Arctic Cloud Experiment field campaign to assess the roles of arctic stratus clouds in the high latitude climate system.

The FIRE Arctic cloud system emphasis beautifully complements the SHEBA (Surface HEat Budget in the Arctic) program and the ARM North Slope of Alaska program.

The FIRE III Upper Tropospheric Cloud Component will adopt the following strategies:

• The continued analysis of the wealth of observations obtained during the FIRE Phases I and II field campaigns and the FIRE extended time observations.
• The definition and execution of limited highly-focused observational programs to complement our current understanding of cirrus cloud systems.
• The assessment of the need for and subsequent definition of a major field campaign focused on tropical upper-tropospheric cloud systems.

In addressing the strategies presented above, FIRE-III recognizes a strong common interest with other programs. Those most directly related include SHEBA (Surface HEat Budget in the Arctic), SASS (Subsonic Assessment Program), DOE/ARM (Department of Energy/Atmospheric Radiation Measurements); MCTEX (Marine Continental Thunderstorm Experiment), GEWEX (Global Energy and Water Experiment); and NSF/ROCEW (National Science Foundation/Role of Clouds, Energy and Water). There is also considerable international activity in these same cloud-climate research arenas. Past FIRE collaboration with scientists from the United Kingdom, France, Germany, and Russia is expected to continue. FIRE welcomes the collaboration with other programs and other countries in its quest to better understand the roles of clouds in the Earth's climate system.