Climate variability and its effect on normalized difference vegetation index (NDVI) using remote sensing in semi-arid area

摘要

In arid and semi areas, understanding the impact of climate variability on vegetation is a key to managing a new adaptation strategy and safeguarding crop production. The aim of this paper is to investigate the relationship between Normalized difference vegetation index (NDVI) and rainfall (R) in the arid area of Gabes. The relationship analysis was carried out in three phases: Firstly, NDVI and LST were derived from Landsat TM (1987,1995), Landsat ETM + (2003) and Landsat 8 Oli/TIRS (2015) using GIS and remote-sensing tools. Then, the trend of LST has been analyzed according to on the obtained map. The rainfall data was homogenized over 10 stations rainfall from 1974 to 2015 using the Regional Vector Method and the variability. It was analyzed using the graphical chronological method in information processing (MGCTI) and tests for rupture detection. Finally, the response of vegetation to climatic parameters was portrayed using zonal statistics. Results show a decrease in rainfall and an increase in LST on 100% of the area. On an annual scale, linear regression reported a positive relation between NDVI and rainfall, while this relation was has been negative between LST and NDVI. Thus, during the study period, the vegetation growth decreased by about 70% in response to the observed climatic variation. The findings show that vegetation growth is affected by rainfall and also by LST. Accordingly, the backup strategy should be based on irrigation management measures monitored by the control of LST.