CHANGES IN VEGETATION VIGOR AND URBAN GREENNESS IN SIX DIFFERENT CITIES OF INDIA―ANALYSIS FROM COARSE RESOLUTION REMOTE SENSING DATASETS

摘要

Urban sprawl is gaining increasing attention in developing countries of the world. With a population of some 1,027 million people, India has more than 10 cities that have one million population. This population is bound to grow and is a major concern of urban sprawl in most of the cities. In this study, we analyze the trends in vegetation greenness patterns in six different cities of India. An attempt has also been made to relate these vegetation changes to population densities. Temporal changes in vegetation vigor from 1984 till 2000 have been analyzed using vegetation greenness index and change detection methodology using NOAA AVHRR remote sensing data. Results from this analysis suggested different patterns of vegetation changes over a period of time. Of the six cities, Hyderabad and Mumbai had similar patterns of vegetation change, where the "vegetation loss" has considerably decreased from 1984 till 2000. Calcutta showed increasing vegetation loss from 1996 to 2000. To infer the patterns of vegetation dispersion resulting from urban sprawl and land development, entropy index has been used. Results from this index suggested that the city of Bangalore had much less dispersion in vegetation compared to Hyderabad and New Delhi. Further, results for Calcutta and Hyderabad suggested that the vegetation has been changing toward concentrated pattern. Results from correlation analysis suggested that as population density increased, the entropy of vegetation greenness decreased in the cities of Calcutta, Bangalore, and Mumbai and Hyderabad compared to Chennai and Delhi. These results suggest that as the density of population increased, the vegetation greenness became more concentrated in these cities. These results on vegetation changes will be useful for urban planners and researchers in addressing some urban climate issues in the rapidly growing cities of India.