Assessing the Impact of Natural Factors on Desertification in Tamilnadu, India using Integrated Remote Sensing

Desertification is one of the major threats to the environment and the global community. Changing climate, deforestation, changing agriculture methods and demand of resources are the important causes for the desertification. Due to dependency of human life on land, monitoring and mitigating the desertification effect is getting more attention over the years. The main objective of the study was to assess the natural factors impact on desertification process on a regional level by using the remotely sensed parameters like TRMM-precipitation, MODIS-evapotranspiration, MODIS-net primary productivity, and ASTER-DEM with the aid of AHP-GIS model. From the above mentioned sensor parameters, the indices like aridity, rainfall, rainfall use efficiency, NPP and slope are prepared for 2000-2012. TRMM data were downscaled to 1km spatial resolution to match the other parameters spatial scale for analysis. All the parameters were classified using the frequency distribution. Based on the classes the ranks were assigned and the weight of the parameters assigned by the expert’s opinions based on questionnaire survey. We converted each data into an annual scale for time series analysis. From the 12 year average data analysis, results showed that, 9.22% of the area is characterized by highly sensitive to desertification which is the southeast part of the state. Most of the area comes under the moderate sensitive area (83.45%) and 4.83% comes under the low sensitive area. The very low sensitive area exhibits only 2.5 %, which is the hilly region of the study area. We discuss the climate parameters, vegetation and topography parameters impact on desertification in the study area.