Influence of land use/land cover (LULC) changes on atmospheric dynamics over the arid region of Rajasthan state, India

The present study examines the long-term effects of land use/land cover (LULC) changes in Rajasthan state, India on land-atmosphere fluxes and, possibly in precipitation and aerosol loading. By comparing the satellite observations from Landsat MSS (1972e73) and IRS-P6 AWiFS (2006e07) considerable LULC changes are observed, an increase in crop-land and vegetated areas of w57% in the eastern and w68% in the western Rajasthan. The increase in agriculture intensification from irrigation activities after the construction of the Indira Gandhi canal (IGC) seems to affect the land-atmosphere fluxes, i.e. increase in atmospheric humidity and latent heat and reduction in sensible heat. On the other hand, the multidecadal variability (1951e2007) in annual rainfall amount and total number of rainy days reveals significant year-to-year fluctuations, exhibiting a slight increasing trend over arid western Rajasthan. However, the overall analysis shows that the variability in precipitation is much more influenced by the general monsoonal circulation (i.e. meteorological dynamics and intensity of the monsoon) and partly can be associated with local phenomena, such as LULC changes and modifications in land-atmosphere fluxes. Similarly to precipitation, the long-term (1979e2008) aerosol index (AI) variations over the region seem to be affected by atmospheric and meteorological dynamics and not by LULC changes.