Quantifying spatial and temporal variabilities of microwave brightness temperature over the U.S. Southern Great Plains

. Spatial and temporal variabilities of microwave brightness temperature over the U.S. Southern Great Plains are quantified in terms of vegetation and soil wetness. The brightness temperatures (TBrpar; are the daytime observations from April to October for 5 years (1979 to 1983) by NIMBUS-7 Scanning Multichannel Microwave Radiometer (SMMR) at 6-6GHz frequency, horizontal polarization. The spatial and temporal variabilities of vegetation are assessed using visible and near-infrared observations by NOAA-7 Advanced Very High Resolution Radiometer (AVHRR), while an Antecedent Precipitation Index (API) model is used for soil wetness. The API model was able to account for more than 50 per cent of the observed variability in TB although linear correlations between TB and API were generally significant at the I per cent level. The slope of the linear regression between TE and API is found to correlate linearly with an index for vegetation density derived from AVHRR data.