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An assessment of the performance of the Geostationary Operational Environmental Satellite (GOES) sounder cloud-top pressure product is presented. GOES sounder cloud-top-height data were compared with values derived from a consensus cloud boundary dataset that utilizes data from a cloud lidar and a cloud radar located at the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Program's Cloud and Radiation Test Bed (CART) site in Lamont, Oklahoma. Comparisons were performed from April 2000 to March 2002. A temporal filtering process was applied to the cloud lidar and cloud radar output so that a representative picture of the cloud field on the same spatial scale of the GOES sounder could be derived. Comparisons between the GOES sounder and ground-based cloud boundary measurements yielded a mean difference of 1772 m and a standard deviation of 1733 m. The difference between GOES cloud-top-height and ground-based retrievals is within [+ or -]500 m for 22% of the retrievals and within [+ or -]1500 m for 56% of the retrievals. These results are comparable to findings in similar studies that utilized the MODIS Airborne Simulator.

Advanced Very High Resolution Radiometer (AVHRR) and Earth Radiation Budget Experiment (ERBE) data are used to obtain radiative energy budget details of oceanic, savanna and desert regions. The AVHRR spectral channels chosen are transparent to clear atmospheric conditions, enabling the study of surface and cloud-top conditions. The ERBE instruments are used to perform broad-band observations for climate studies.

Cloud and cloud attributes in the infrared can be identified using trispectral combination of observations at 8-, 11- and 12-micrometer bands. Cloudy and clear regions are indicated by positive 8-11-micrometer tightness temperature differences and near-zero or negative differences, respectively, as a result of the peaking of atmospheric ice and water vapor absorption in opposite halves of the window area. The absorption coefficient for ice rises less between 11 and 12 micrometer than between 8 and 11 micrometer.

The influence of airborne dust on the radiative energy budget at the top of the atmosphere was determined using the Earth Radiation Budget Experiment data and model. Results show that the presence of the dust particlesat the top of the atmosphere has caused the rise of clear-sky shortwave radiative exitance (SWRE) over the ocean, while the longwave radiative exitance(LWRE) was reduced. However, the SWRE over the desert was not clearly measured by satellite readings, but the LWRE results over the desert featured a reduction similar to the ocean observations.

This paper investigates the relationship between high--spectral resolution infrared (IR) radiances and the microphysical and macrophysical properties of cirrus clouds. Through use of radiosonde measurements of the atmospheric state at the Department of Energy's Atmospheric Radiation Measurement Program site, high--spectral resolution IR radiances are calculated by combining trace gas absorption optical depths from a line-by-line radiative transfer model with the discrete ordinate radiative transfer (DISORT) method. The sensitivity of the high--spectral resolution IR radiances to particle size, ice-water path, cloud-top location, cloud thickness, and multilayered cloud conditions is estimated in a multitude of calculations. DISORT calculations and interferometer measurements of cirrus ice cloud between 700 and 1300 [cm.sup.-1] are compared for three different situations. The measurements were made with the High--Spectral Resolution Interferometer Sounder mounted on a National Aeronautics and Space Administration ER-2 aircraft flying at 20-km altitude during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS).