Remote sensing based agricultural drought assessment in Palar basin of Tamil Nadu state, India
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Photonirvachak
J. Indian Soc. Remote Sens. (March 2009) 37:9–20
RESEARCH ARTICLE
Remote Sensing Based Agricultural Drought Assessment in Palar Basin of Tamil Nadu State, India T. Murali Krishna . G. Ravikumar . M. Krishnaveni
Received: 9 July 2007 / Accepted: 16 December 2008
Keywords Drought assessment . Remote sensing . WiFS . NDVI
Abstract Agricultural drought has been a recurrent phenomenon in many parts of India. Remote sensing plays a vital role in real time monitoring of the agricultural drought conditions over large area, there by effectively supplementing the ground mechanism. Conventional drought monitoring is based on subjective data. The satellite based monitoring such as National Agricultural Drought Assessment and Monitoring System (NADAMS) is
T.M. Krishna1 ( ) . G. Ravikumar2 . M. Krishnaveni1 Centre for Water Resources, CEG, Anna University, Chennai – 600 025, India Asst. Professor in Civil, 2 Department of Chemical Engg, A C Tech, Anna University, Chennai – 600 025, India
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email : [email protected]
based on the crop condition, which is an integrated effect of soil, effective rainfall, weather, etc. Drought causes changes in the external appearance of vegetation, which can clearly be identified (by their changed spectral response) and judged using satellite sensors through the use of vegetation indices. These indices are functions of rate of growth of the plants and are sensitive to the changes of moisture stress in vegetation. The satellite based drought assessment methodology was developed based on relationship obtained between previous year’s Normalised Difference Vegetation Index (NDVI) profiles with corresponding agricultural performance available at district/block level. Palar basin, one of the major river basins in Tamil Nadu state was selected as the study area. The basin covers 3 districts, which contain 44 blocks. Wide Image Field Sensor (WiFS) of 188m spatial resolution from Indian Remote Sensing Satellite (IRS) data was used for the analysis. Satellite based vegetation index NDVI, was generated for Samba and Navarai
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seasons in the years 1998 and 1999. An attempt has been made to estimate the area under paddy. It was also observed that, there was reduction in the crop area as well as vigour in the vegetation in both Samba and Navarai seasons in 1999 when compared with 1998. Drought severity maps were prepared in GIS environment giving blockwise agricultural water deficiency status.
Introduction Agriculture is the main stay in India with 69% of the population depending on it. India has a total geographical area of 328 Mha, out of which the total cropped area is 174 Mha including 142 Mha rainfed area. Drought, meaning water deficiency, is considered to be one of the man’s worst natural enemies. Its beginning is subtle, progress is insidious and effect can be devastating. It causes critical water resources policy problems involving conservation, development and control issues and relief management in many regions of a country. Increased demands on water supplies will
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