Assessing the impact of land-use and land-cover changes on the climate over India using a regional climate model (RegCM4)

Changes in land use and land cover (LULC) in recent decades are among the factors responsible for recent climate change. We assessed the impact of LULC changes on the climate over India through multi-decade simulations (3 decades) using the Regional Climate Modeling system (RegCM4) with fixed and changed LULC. Differences between the 2 simulations were considered to be impacts of LULC changes on the regional climate. The main focus was on the decadal climatology of temperature, precipitation and several other important climatic variables including specific humidity, moisture content, sensible heat, evapotranspiration over Indian regions and their responses to the LULC changes. We found a decreasing trend in annual precipitation and increasing trend in annual temperature over India during 1981-2010. The LULC changes over northwest, south peninsular and west-central regions of India contributed to warming during 1991-2010, while changes over central-north and northeastern regions resulted in cooling during this period. LULC changes also indicated a wet effect over south peninsular and west-central regions of India and a dry effect over northwest India in 1991-2010. The analysis indicated that LULC changes resulted in decreases in evapotranspiration, moisture content and specific humidity that led to decreased precipitation. On the other hand, changes in LULC also caused significant increases in sensible heat flux and albedo, which led to a temperature rise. Our overall modeling results further our understanding of the processes associated with LULC change feedback to the climate over Indian regions.