Studies on Temporal Relationship between Normalized Difference Vegetation Index and Rainfall in the Southern Part of Ethiopia

Abstract

Nowadays remote sensing has become a powerful tool for many aspects of global monitoring for its convenience and high efficiency. This study analyzed temporal distribution of normalized differences vegetation index (NDVI) on the southern Ethiopia and their correlation with rainfall factors from 1995 to 2004. Monthly and annual data of NDVI and rainfall are examined to determine the consequence of rainfall variability on the NDVI of vegetation cover. Normalized Difference Vegetation Index (NDVI) data from  the National Oceanic and Atmospheric Administration (NOAA) satellites and rainfall data from National Meteorology Agency (NMA) were used to investigate the temporal pattern of rainfall and  the response  of vegetation to rainfall in Southern part of Ethiopia. Thus, NDVI is an important variable for climate applications and agricultural productions. It is also important to study the NDVI for different seasons and at different agro-ecological areas to investigate its effects. The temporal pattern of NDVI and rainfall revealed that vegetation responded directly to rainfall. The temporal patterns showed that there was between 0 to 1 months lag between rainfall and vegetation. However it was not possible to draw conclusion regarding the annual and monthly relationship between rainfall and NDVI because, it is not solely explained by rainfall parameter. Determining time series relationship between rainfall and vegetation (NDVI) will improve the prediction of local level rainfall distribution. Effective dissemination of this information to stakeholders will enhance the suffering of communities from vulnerability to climate related risk by improving their management.

Keywords: NDVI, Rainfall, Correlation, Variability, Southern Ethiopia