The Atmospheric Radiation Measurement (ARM) Program conducted a Cloud Intensive Operational Period (IOP) in March 2000 that was the first-ever effort to document the 3-dimensional cloud field from observational data. Prior numerical studies of solar radiation propagation through the atmosphere in the presence of clouds have been limited by the necessity to use theoretical representations of clouds. Three-dimensional representations of actual clouds and their microphysical properties, such as the distribution of ice and water, had previously not been possible because instrumentation appropriate to the task was not available.

This case study presents data from 1 March 2000 to 31 March 2000 and covers a region from 25N to 45N latitude and from 120W to 80W longitude.

Cloud Optical Thickness vs. Cloud Top Pressure Frequency Histogram To download this data, go to the GCSS-DIME ftp site (ftp gcss-dime.giss.nasa.gov/pub/ARM-00/CLIMCOMP).

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