Apparent thermal inertia study over Delhi-NCR (National Capital Region) (Conference Presentation)

Abstract

This study attempts to examine the role of apparent thermal inertia in the variable behaviour of day-time and night-time Urban Heat Island formation over Delhi. LISS-III data of Resourcesat-I has been used for land-use/land-cover classification and MODIS data have been used for land surface temperature and surface albedo. The albedo map shows that albedo over Delhi is significantly less (~ 0.08 to 0.13) over major part of Delhi, while albedo in its surrounding regions ranges from 0.15 to 0.2. This suggests that a significantly greater fraction of the incoming solar radiation is utilized for heating up of land surface over Delhi as compared to its surrounding regions. The night-time land surface temperature maps reveal that temperatures over Delhi are significantly higher (8°C -10°C) than those over the surrounding regions showing the formation of nocturnal heat island. However, a cool island is observed in the month of May during the day-time. The day and night time temperature maps are then used to obtain the diurnal temperature range and together with albedo maps of the study region, are used to estimate the apparent thermal inertia over the region. The study reveals that the dense built-up urban area of Delhi has higher apparent thermal inertia than that of the surrounding rural areas during the study period.