Estimating minimum and maximum air temperature using MODIS data over Indo-Gangetic Plain

Spatially distributed air temperature data are required for climatological, hydrological and environmental studies. However, high spatial distribution patterns of air temperature are not available from meteorological stations due to its sparse network. The objective of this study was to estimate high spatial resolution minimum air temperature (T (min)) and maximum air temperature (T (max)) over the Indo-Gangetic Plain using Moderate Resolution Imaging Spectroradiometer (MODIS) data and India Meteorological Department (IMD) ground station data. T (min) was estimated by establishing an empirical relationship between IMD T (min) and night-time MODIS Land Surface Temperature (T (s)). While, T (max) was estimated using the Temperature-Vegetation Index (TVX) approach. The TVX approach is based on the linear relationship between T (s) and Normalized Difference Vegetation Index (NDVI) data where T (max) is estimated by extrapolating the NDVI-T (s) regression line to maximum value of NDVImax for effective full vegetation cover. The present study also proposed a methodology to estimate NDVImax using IMD measured T (max) for the Indo-Gangetic Plain. Comparison of MODIS estimated T (min) with IMD measured T (min) showed mean absolute error (MAE) of 1.73A degrees C and a root mean square error (RMSE) of 2.2A degrees C. Analysis in the study for T (max) estimation showed that calibrated NDVImax performed well, with the MAE of 1.79A degrees C and RMSE of 2.16A degrees C.