Greening trends of the Indian landmass

摘要

Spatio-temporal patterns of the vegetation during the temporal span of 25 years (1982-2006) using GIMMS data was analyzed to explore the vegetation trend on the Indian landmass. To understand the interannual trends in vegetation activity, the pixel-specific Area under the Annual NDVI Time-series (AANT) was computed. The results indicated that the agricultural practices played an important role in influencing the NDVI greening trends over some regions. In order to analyze the trends for different agro-ecological zones of India, we used the Indian Meteorological Department sub-divisional map to perform the data analysis. Highest significant positive trend was found in agro-ecological zones of Marathwada (r2 = 0.85*), Vidharba ( r2 = 0.64*), Madhya Maharashtra ( r2 = 0.85*), Rayalseema( r2 = 0.746*), North Interior Karanataka( r2 = 0.61*), Gujarat ( r2 = 0.63*), East Rajasthan ( r2 = 0.65*), and West Madhya Pradesh( r2 = 0.62*). To explore the temporal trends that are season-specific, Areas under theSeasonal NDVI Trajectories was also calculated. Greening trend was found to be season specific and was mainly related to agriculture practices. The region which showed significant positive trend coincides with the region where area under irrigated agriculture increased during this period. Agriculture practices involving irrigation and fertilization may have contributed to the increased NDVI in these regions (*significant P<0.05).