
| CERES | Documents | Operations | Pictures | Quick-Look Results | Related Activities | Terra |


| These pictures show examples of the first measurements
that the CERES instruments on the Terra satellite have made. We use
data products such as these to validate the accuracy of our Earth energy estimates. As
we gain confidence in the proper operation of the instrument and the data interpretation
algorithms, the science data products will be archived at the Langley Distributed Active Archive Center (DAAC). Contributions to these pages are welcome.
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Reflected Solar Radiances - 2/26/2000 - This image shows reflected solar radiance emerging from the top of the atmosphere, as measured by the CERES Flight Model 1 (FM1) instrument on the Terra spacecraft. These preliminary (unvalidated) data show twenty four hours of measurements covering the entire Earth from North Pole to South Pole. (For more info...) |
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Reflected Shortwave Flux - 2/26/2000 - This image shows the reflected solar
flux emerging from the top of the atmosphere. The data are taken from an
entire day of observations from the CERES Flight Model 1 (FM1)
instrument on the Terra spacecraft. The quantity plotted is "reflected solar flux," which not only
involves instrument calibration and geolocation, but also removes the angular dependence of the
upwelling radiance field. Thus, these data are Level 2 data, which means
that CERES has been
able to get a reasonable "engineering" calculation of derived physical fields within a few days of
opening its covers. The data shown come from Saturday, February 26, 2000,
the first full day of FM1 scanning. (For more info...) |
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Emitted Longwave Flux - 2/26/2000 - This image shows the energy being lost from the Earth and the atmosphere by thermal emission. This process, familiar to most of us as the heat radiated by electric stove elements, involves light with wavelengths invisible to the eye. Again, these data are Level 2 data from Saturday, February 26, 2000. (For more info...) |
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This picture shows Terra and TRMM data as the two satellites cross each other's path (also see image below). The black dots and red circles represent Terra and TRMM data, respectively. The 70 black dots inside red circles correspond to overlapping Terra and TRMM measurements. To compare their data directly, the two instruments must look at their target from the same viewpoint. The 17 blue dots show the matched Terra and TRMM measurements of radiation emitted by the Earth (LW) while the 7 yellow dots are matched measurements of reflected solar radiation (SW). The difference between Terra and TRMM is on the order of 1% or less, but the variability is large (2.5-5%). To improve the confidence in our comparisons we must collect data from many such overlaps. |
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On March 3, 2000, the CERES team began joint operations with TRMM and Terra to compare the performance of the instruments on each satellite. This picture shows a comparison on March 4 with the Terra satellite moving north to south and the TRMM satellite moving west to east at nearly the same time. At the orbit crossing point, we rotate the scan plane of CERES FM1 on Terra to match the scan plane of TRMM. This event is over the northern Pacific and shows a bright cloud (in red) at the crossing point. Many such crossings are needed to gain confidence in the accuracy of the measurements. |
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CERES Terra FM1, 2/29/00, Hour 2, CERES Total Filtered Radiances Upward. Instrument is in the crosstrack, normal- earth scanning configuration. The spacecraft is descending over the Phillipines. Note the overlapping biaxial data from the corresponding FM2 data plot. |
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CERES Terra FM2, 2/29/00, Hour 2, CERES Total Filtered Radiances Upward. Instrument is in the biaxial, normal- earth scanning configuration. The spacecraft is descending over the Phillipines. Note the overlapping crosstrack data from the corresponding FM1 data plot. |
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CERES Terra FM2 - 2/27/2000 - CERES Total Filtered Radiances Upwards for Data Range: 01:58:44 - 02:53:57. Instrument is in the crosstrack, normal-earth scanning configuration. The spacecraft is descending over the Phillipines. The sun viewing zenith can be seen by the horizontal line just below the equator and the line runs east to west during this period. |
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CERES Terra FM1 - 2/26/2000 - CERES Total Filtered Radiances Upwards for Data Range: 01:15:04 - 02:44:57. Instrument is in the crosstrack, normal-earth scanning configuration and the period is within one hour of commencing science operations after the covers were opened. The spacecraft is descending over the Phillipines. The sun viewing zenith can be seen by the horizontal line just below the equator and the line runs east to west during this period. |
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