Monday, 3 June 2002
Comparison of MODIS cloud mask (MOD35) and MODIS cloud property (MOD06) results with similar properties derived from ARM data.
The MODIS instrument on board the TERRA satellite has been collecting data since early in the year 2000. This instrument measures the upwelling radiation in several narrow spectral channels at a nominal resolution of 1 km in a 2300 km swath under the satellite track. From the measured radiances, the properties of clouds are derived using various algorithms. We have been monitoring the TERRA ephemeris for times when the satellite passes close to a ground site operated by the Atmospheric Radiation Measurement (ARM) Program. Under acceptable conditions determined by the satellite view zenith and the existence of quality ground based data, we compare the cloud properties derived by the cloud mask algorithm (MOD35) and the cloud microphysical properties algorithm (MOD06) to similar properties derived from algorithms applied to cloud radar, lidar, and radiometer data observed at the surface. We will present results of these comparisons. Specifically, we will present individual case studies of several cloud types including thin cirrus, thick cirrus and boundary layer stratus. Comparison results will also be presented in a statistical format so that some sense of therelative agreement between the algorithm results can be ascertained.
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