Spatio-Temporal Variability of Spectral Indices and Land Surface Temperature for Ecological Change Detection in Faridabad District India Between 1991 and 2021

Increasing urban populations and the associated decay of green cover, increasing surface temperature results in degradation of ecological quality worldwide, including India's growing cities. Faridabad region in the north-western semi-arid part India experienced a major urban-industrial growth in past few decades and still lacks enough attention from the research community. To fill that data scarcity, a long term assessment of ecological quality over 30 years is attempted in this area. Assessment of ecological quality of an area is dynamic as it is related to various ecological parameters like greenness, moisture, dryness and built up density. Hence, single factor based assessment of ecological quality is inadequate for holistic view. Therefore, the present research attempts to assess the ecological status using remote sensing based composite ecological index which is computed by aggregating four indices Soil Adjusted Vegetation Index (SAVI), Normalized Difference Moisture Index (NDMI), Normalized Difference Soil Index (NDSI) and Normalized Difference Built-up Index (NDBI) representing aforementioned ecological parameters. In addition, all these parameters are correlated with the land surface temperature (LST) to demonstrate the impact of land cover conversion on surface temperature and climatic warming. Positive correlation of NDSI and NDBI with LST and negative correlation of SAVI and NDMI with LST revealed that the replacement of green spaces with concrete structures leads to the absorption and retention of heat, further exacerbating the overall temperature rise. Overall in study area, ecological degradation associated with high LST is observed in the central and northern part due to urban-industrial growth. Notable ecological improvement occurred near the Yamuna River due to the rejuvenation initiatives. Such finding motivates the planner to innovate smart green measures while designing the incipient smart cities. Further present research findings are helpful to identify the hotspot of ecological degradation and contribute to the micro-planning of mitigation measures to conserve the urban ecology.