Comparison of TOVS-derived land surface variables with ground observations

The Tires Operational Vertical Sounder (TOVS) Pathfinder Path A retrieved s urface skin temperature, surface air temperatures, and surface specific hum idity are compared with data obtained from three large-scale field campaign s: the First ISLSCP (International Satellite Land Surface Climatology Proje ct) Field Experiment (FIFE), the Hydrologic Atmospheric Pilot Experiment (H APEX) in the Sahel, and the Boreal Ecosystem-Atmosphere Study (BOREAS). The long-term estimates of surface skin temperatures, surface air temperatures , and surface vapor pressure were unbiased, and the standard deviations of the errors were about 4 degrees C, 3.5 degrees C, and 3.5 mbar, respectivel y. The monthly mean variables obtained from the TOVS data at four times of the day (corresponding to the AM and PM overpass for each of two satellites ) exhibited realistic diurnal and seasonal cycles when compared with corres ponding ground observations.