Vegetation Sensitivity to Changing Climate in Bangladesh Using SPOT-VGT NDVI Time Series Data

Abstract

The Normalized Difference Vegetation Index (NDVI) has found a wide application in vegetative studies as it has been used to estimate changes in vegetation health, vegetation cover, croplands, drought, grasslands, rangeland, etc. It is also associated with surface water, biomass range, photosynthetic level, and leaf area index. The main objective of this study is to assess the variability of vegetation health and its relationship with climatic attributes in Bangladesh. Here, 10-day SPOT-Vegetation Normalized Difference Vegetation Index (NDVI) time series data for the period 1998 to 2013 with 1 km resolution was used to study the vegetation changes in Bangladesh on the basis of 26 study sites based on the GLC 2009 land use categories. The frame work for the analysis is the use of correlation and coefficient of determination (R2) to determine the temporal changes of NDVI based on 800 spatially distributed random points in Bangladesh for the same period. A Pearson’s correlation coefficient was used to define the relationship of monthly growing season NDVI with monthly rainfall and temperature derived from CRU TS 3.2 datasets. And analysis of 30- and 60-day lag rainfall was also figured. The result shows that there was a fluctuation in the vegetation growth during the wettest months for each year. The analysis between climatic attributes and NDVI during the period 1998–2013 showed a negative correlation. Thus from the analysis it emerged that the negative correlation between NDVI and precipitation and slightly positive correlation with temperature was emphasized during the growing season.