Spatio-temporal Analysis of Aridity Over Punjab Province, Pakistan using Remote Sensing Techniques

Abstract

Aridity is a severe threat to the ecological environment and it leads to desertification. Aridity has become a more serious hazard to agricultural countries like Pakistan, followed by socio-economic problems. Pakistan is an agrarian country and Punjab province of Pakistan is known as the basket of grain for its population due to its fertile lands and lush green fields. Less or no rainfall can convert any land or region from humid to semi-arid and semi-arid to arid land. Deficiency of moisture also defines arid conditions of any region. Hence, in case of Punjab, aridity is a severe threat to halt the use of full potential of its agricultural land resources. There is an irresistible need to comprehensively assess aridity in Punjab at different time scales and to formulate necessary arrangements and action plans to face this issue on sound footing. Remote sensing can be used to accurately measure aridity on local, regional and global scales. Multi-temporal images of Moderate-resolution Imaging Spectroradiometer (MODIS) MOD13Q1 and MOD11A1 of Punjab province are used for aridity assessment. In this study attempt was made to demarcate arid areas of Punjab in the simplest possible form using different vegetation indices and land surface temperature. Maps are developed by using normalized difference vegetation index (NDVI), transformed normalized difference vegetation index (TNDVI), soil adjusted vegetation index (SAVI) and land surface temperature (LST). A weighted overlay analysis of these indices was also done for further comprehensive analysis of aridity. The results indicate that aridity is more in southern Punjab due to increased temperature and reduced precipitation and in northern regions of the province, aridity is developing especially in those areas, which were semi humid or semi-arid in the past.