An assessment of the correlation between rainfall and the Normalized Difference Vegetation Index (NDVI) over Iraq

Abstract

The Normalized Difference Vegetation Index (NDVI) is one of the earliest spectral indices developed to monitor vegetation dynamics and assess changes over time. Climatic conditions, particularly rainfall, play a significant role in shaping the distribution and density of vegetation, especially in urban and semi-arid environments. The study aims to use remote sensing techniques to find out how dense vegetation cover is in Iraq, how it has changed over time, and how NDVI and rainfall are related. We applied the NDVI to 264 monthly satellite photos from NASA’s MODIS sensor, captured between 2000 and 2021. The study looked at changes in NDVI and rainfall data over the same period to find trends in the two variables throughout space and time. The results showed that vegetation cover changed a lot over the years of the study. Climate variables, especially rainfall, directly affected whether vegetation grew or shrank. There was a modest positive link between NDVI and rainfall, with a correlation coefficient 0.5. This means that more rain usually means more vegetation growth and activity. The data also showed that the NDVI values were greater in the northern and eastern Iraq than in the southern and western parts. This was because the north has many mountains and a fairly humid climate. Over time, the vegetation in the central region slowly decreased because of urban growth and less rain. These findings show how important it is to combine NDVI and rainfall data for effective management of land and water resources and to find locations with more potential for farming.