Impact of climatic parameters on NDVI in Mahanadi Catchment, India

Abstract

This report presents the analysis of interannual and seasonal vegetation trends (i.e., Greening and Browning) based on the data derived from satellite images using Normalized Difference Vegetation Index (NDVI) and its response with Climate extremes over the Mahanadi catchment, using the MODIS NDVI produced on 16-day intervals and at multiple spatial resolutions for the period 2001 to 2019. NDVI and climatic parameters trend analysis methods and correlation analysis are applied. From the results, a greening (positive) trend in the annual NDVI and the monsoon NDVI has been observed, whereas the annual rainfall showed a negative trend and annual temperature showed a positive trend. All the extreme precipitation indices, that is, Consecutive dry days (CDD), Consecutive wet days (CWD), torrential rainfall days (R24), precipitation days (R0.1), showed a negative trend. The temperature extremes indices; Mean maximum temperature (Txav) and mean minimum temperature (Tnav), showed a positive trend. From the correlation analyses, a negative and weak correlation has been found between NDVI and precipitation extreme indices, and a positive correlation has been found between Mean minimum temperature and NDVI. A positive correlation exists between NDVI and Rainfall during the Monsoon season. 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 has a possible positive impact on the vegetation ecosystem.