Comparison of surface meteorological variables from TOVS and AVHRR

This paper examines, on global and continental spatial scales, the relationship between surface meteorological observations retrieved from the Advanced Very High Resolution Radiometer (AVHRR) and the TIROS Operational Vertical Sounder (TOVS). Comparisons of spatial and temporal patterns of surface temperature, air temperature, and vapor pressure deficit were carried out using data acquired between January 1989 and December 1990 on a monthly time step. These variables play an important role in hydrological, ecological, and land surface–atmosphere interactions. Additional comparisons were done for seven large regions (ca. 106 km2) centered on the continental land surface areas in order to test for regional differences and to reduce the effect of coastal transition zones on spatial resampling. The mean statistical differences between the TOVS and AVHRR estimates were 5 °C for surface temperature, 4 °C for air temperature, and 1.5 kPa for vapor pressure deficit. In addition to long-term and spatially extensive ground data sets, these comparisons provide independent validation of different estimation methods using various satellite sensor measurements resampled to comparable spatial scales. Favorable comparison of the two sensors considered here provide greater confidence in the use of these data sets for global monitoring and modeling applications.