Geospatial Application in Desertification Monitoring-Rajasthan, India

International Journal of Research and Scientific Innovation (IJRSI) | Volume VIII, Issue III, March 2021 | ISSN 2321–2705

Geospatial Application in Desertification Monitoring-Rajasthan, India

K.Rajendram¹ &  N.R.Patel²

¹Department of Geography, Eastern University,Sri Lanka
Chenkalady, 30350,
(Formerly PGD Scholar, CSSTEAP, IIRS, India)
²Indian Institute of Remote Sensing (IIRS),
Indian Space Research Organization, No4, Kalidas Road,
Dehradun, India.

Abstract –
Desertification is a significant environmental problem in the arid and semi-arid regions, mainly caused by climate variations, change, and anthropogenic activities. The characteristic of rainfall of Rajasthan is seasonal, erratic, and higher variability is resulting in increasing aridity and degradation of vegetation growth and desertification. This study’s prime objective is to analyze vegetation trends using long-term NDVI from AVHRR for desertification monitoring. Surface vegetation is the most important indicator to assess desertification. In this study, long-term NOAA-AVHRR-GIMMS3G (1983-2011) Normalize Difference Vegetation Index (NDVI) time trends were used as a proxy for Net Primary Production (NPP). To assess the vegetation trend, annual, seasonal, and monthly NDVI, and its mean, maximum, standard deviation, and NDVI Anomaly Index, integral NDVI (iNDVI) were computed. Spatial and temporal variability rainfall and drought were studied using monthly rainfall data from 1983 to 2011 for 102 rain gauge stations. Standardized Precipitation Index (SPI) was computed for all rain gage stations then the SPI results were interpolated. The iNDVI/RF trends were estimated to assess the desertification processes. The 3-month SPI and NDVI anomaly index’s spatial pattern during drought years have a higher negative anomaly during the months from July to September in the greater part of Rajasthan. For example, in 2002, higher SPI values were noticed at Bikaner (August, -3.33, July,-3.13, and September, -2.76) and Chirawa (September,-3.02, August, -2.41). The trends of iNDVI/RF ratio results suggest that about 37 % of the study area was experienced decreasing trends of vegetation growth, ongoing degradation, and desertification process. The districts of Jaisalmer, Jodhpur, Nagaur, Sikar, Bikaner, Churu, and the northwestern part of Barmer are mostly affected by land degradation. About 45% of the study area was experienced the stable condition. Only 9% showed strong positive trends in vegetation growth.

Keywords: Desertification, Land Degradation, NDVI Anomaly Index, iNDVI/RF trend, Vegetation growth

1. INTRODUCTION

Desertification refers to land degradation in dry lands. Desertification is characterized by the spread of desert conditions beyond desert margins or by the intensification of desert conditions within arid regions, which is accompanied by diminished productivity. According to United Nations Convention to Combat, Desertification definition refers to the degradation of land in arid, semi land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variation and human activities (UNCCD, 1994, UNEP, 1992). Desertification is when land becomes dry, bare and unsuitable for growing trees or crops. Desertification is considered a severe environmental problem mainly caused by climate changes and human
activities during the last decades (Kundu et al. 2014, Elhag et al. 2014, UNEP, 1992). The United Nations to Combat Desertification (UNCCD) programme was approved by 195 countries which mainly focus the desertification and land degradation (UNCCD, 1994). Nearly one-third of the global land surface is under the

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