Modeling of land-use and land-cover change impact on summertime near-surface temperature variability over the Delhi-Mumbai Industrial Corridor

This study explores the impact of land-use and land-cover (LULC) changes due to different urbanization scenarios in the Delhi-Mumbai Industrial Corridor (DMIC) region on surface air temperature by conducting sensitivity studies with the Weather Research and Forecasting (WRF) model. First, a sensitivity analysis conducted using the planetary boundary layer (PBL) and surface layer (SL) physical parameterizations available in WRF. Results show that the model performs better when a combination of the Mellor-Yamada-Janjic PBL and ETA SL schemes used. Then, numerical experiments performed using WRF with the above configuration and three different LULC scenarios to assess the possible impact of urbanization on near-surface temperature during May. A total of ten simulations were conducted for the May month of 2005-2014 to estimate the statistical and physical robustness of results. Each of these simulations considered as ensemble member while computing average values. The study shows that there is a significant effect of LULC change mainly on the minimum temperature (T-min) with an increase of 2.9-3.7celcius over the DMIC region. The impact is less on maximum temperature, with a minor rise in 0.1-0.3celcius. The probable reason for the increase in minimum temperature is likely due to a decrease in latent heat flux and an increase in sensible heat flux. The impact on air temperature was found to be prominent over existing urban clusters than the surrounding built environment; also, this effect is additive and more pronounced with the extreme LULC change scenario.