Changing pattern of urban landscape and its effect on land surface temperature in and around Delhi

摘要

The last couple of decades have seen remarkable spatial growth in the urban areas of developing countries. The process of urbanization is directly linked with land transformation which can be an effective way to monitor the spatio-temporal pattern of urban growth. New Delhi, the capital city of India has experienced a large-scale urban growth during the last decade. In order to identify the pattern of urban expansion in and around Delhi, the present study aims to assess the process of land transformation using multi-temporal Landsat datasets (1977-2014). The areas under various land use and land cover (LULC) extracted by support vector machine (SVM) hybrid classifier reveal asignificant change in the LULC pattern of the area. A good agreement was found between field-based information and maps generated using satellite images (kappa >= 0.84). Land transformation maps indicate rapid growth of few urban centres located outside Delhi National Capital Territory (NCT), like Gurgaon, Gautam Buddha Nagar, Faridabad and Ghaziabad. These centres have been remarkably expanded because of transformation of agricultural and vegetated lands. However, green patches within the city have not been affected by the consequences of urbanization. In tune with the rapid urbanization in the periurban centres of Delhi, the Moderate Resolution Imaging Spectro-radiometer (MODIS)-derived land surface temperature (LST) images revealed significant change in the level of LST. The inter-relationship of impervious surface fraction (ISF) and LST proves a good agreement between them. The increasing trend observed in the long-term (1987-2011) summer temperature data obtained from India Meteorological Department (IMD) indicates the rise of mean summer temperature in the last few decades. Land transformation along with rapid urbanization especially in the periurban areas of Delhi NCT played a key role in the increasing trend of surface temperature.