INTERLINKAGES OF NOAA AVHRR DERIVED INTEGRATED NDVI TO SEASONAL PRECIPITATION AND TRANSPIRATION IN DRYLAND TROPICS/

Citation
Sk. Srivastava et al., INTERLINKAGES OF NOAA AVHRR DERIVED INTEGRATED NDVI TO SEASONAL PRECIPITATION AND TRANSPIRATION IN DRYLAND TROPICS/, International journal of remote sensing, 18(14), 1997, pp. 2931-2952
Citations number
39
Categorie Soggetti
Photographic Tecnology","Remote Sensing
ISSN journal
01431161
Volume
18
Issue
14
Year of publication
1997
Pages
2931 - 2952
Database
ISI
SICI code
0143-1161(1997)18:14<2931:IONADI>2.0.ZU;2-3
Abstract
The NOAA/AVHRR derived Normalized Difference Vegetation Index (NDVI) o ffers immense potential to study dryland ecosystems. Its relation with rainfall in semi-arid regions is both sensitive and complex. The phys ical basis of this relation is vegetation, mainly grown due to soil mo isture availability as the result of the seasonal rainfall, which inte rcepts photosynthetically active radiation (PAR) and hence directly in fluences the aggregate of NDVI. While the major part of rainfall is lo st through direct evaporation from the soil surface, run-off and drain age, a small fraction of rain water which is used by crops for their g rowth and yield, is a key parameter linking rainfall with NDVI, especi ally in dryland tropics. The extent of non-utilized rain water depends not only on the local weather parameters but also on optimal land and water management practices along with the cropping pattern having eff icient radiation use efficiencies. Although there have been several st udies reporting the relation between AVHRR NDVI and rainfall in semi-a rid regions the sensitivity of this relation in varying dryland condit ions has rarely been analysed quantitatively. The present study aims t o interpret seasonal AVHRR NDVI variations with the seasonal aggregate of rainfall and fraction of soil moisture used by vegetation in the s ix drought prone districts of Karnataka State, India representing very severe, severe and moderate drought conditions. Area averaged seasona l transpiration which has been theoretically linked to integrated NDVI (INDVI), has been realized up to a certain extent in the study areas. The study reveals a closer AVHRR NDVI relation with the water used by vegetation for its growth and yield than the precipitation in dryland ecosystems.