ANNOUNCEMENTS
The expeditious urbanization and population growth have a crucial footprint on the climatic conditions. The continuous increase of urban populace and impervious earth surfaces led to the vast increment of UHI effect in the urban areas of developing countries, provoking a fall off in thermal comfort. Therefore, the present study is an attempt to examine the diurnal, spatio-temporal and seasonal trend of UHI in Delhi NCR from 2010-2020 by using LST data of MODIS satellite. To accomplish this aim, an in depth analysis of LST and its association with meteorological parameters (rainfall and wind), aerosols and land use land cover indices (NDVI, NDBI and NDBaI) has been quantified. The results revealed that daytime LST is strongly related with fallow and barren land cover. However, the nighttime LST is strongly associated with the built-up land use, indicating the phenomenon of fallow, bare land, and urban areas developing UHI during the daytime and night time, respectively. The areas dominated by vegetation, water bodies and forest demonstrated lower land surface temperatures compared to parts of Delhi NCR dominated by rural built-up and agricultural land. The forming pattern of urban heat islands in the urban areas of Delhi is recognised from the pattern that the diurnal variation in the LST affects diurnal UTFVI. Trend was identified where areas with extremely high LST values in summer months, also experienced extremely low temperatures in winter. A negative correlation was identified when LST was correlated with Rainfall and Aerosols. The association of LST with lulc change shows that substantial variation has occurred in LULC with gradual increase of built-up areas and decrease in the barren and agricultural land during the study time period. The coefficient of determination examines that the impact of NDBI on the LST is highest while NDVI has the least impression on LST. Thus, the study suggests that the increase of surface temperature in the urban area is a consequential effect of change in LULC pattern, decrease of vegetation and the rapid growth of man-made built-ups.
Keywords: Urban Heat Island, Land Surface Temperature (LST), Aerosol Optical Depth (AOD), Urban thermal feld variation index (UTFVI), Land Use Land Cover (LULC), LANDSAT, MODIS.
