IMPACT OF CLIMATIC PARAMETERS ON NDVI IN INDIA

Abstract

This report presents the analysis of interannual and vegetation trends (i.e., Greening and Browning) based on the data derived from satellite images using the Normalized Difference Vegetation Index (NDVI) and its response to Climate extremes over India, using the MODIS NDVI produced on 16- day intervals and at multiple spatial resolutions for the period 2001 to 2020. NDVI and climatic parameters trend analysis methods and correlation analysis are applied. The results show a strong significant greening (positive) trend in the annual NDVI, whereas the annual rainfall slightly increasing trend. Extreme precipitation indices, that is, Consecutive dry days (CDD) showed decreasing trends, Consecutive wet days (CWD), and torrential rainfall days (R24) showed a significantly increasing and decreasing trend, whereas precipitation days (R1), showed significant greening trends. The temperature extremes indices; Mean maximum temperature (Txav) and mean minimum temperature (Tnav), showed a significant positive trend. From the correlation analyses, a weak or insignificant correlation has been found between NDVI and precipitation extreme indices (R24 and R0.1), whereas a relatively stronger negative correlation has been found between the NDVI and (CDD and CWD), negative and weak correlation has been found between NDVI and annual precipitation, and a positive correlation has been found between Mean minimum temperature(Tnav) and NDVI, and a negative correlation has been found between Mean minimum temperature(Txav) and NDVI. The results indicate that the decrease in precipitation extremes may trigger the NDVI increase over the last two decades. A slight increase in the mean minimum temperature can positively impact the vegetation ecosystem.