Rangeland drought monitoring using MODIS based data in Iran 1386-1388
2011
Fatehi Marj, Ahmad | Davoodi, Mohammad Hadi | Bagherinia, Mozhgan
Drought monitoring has a key role in damage reduction in agricultural economy. Lack of meteorological stations and deficiency in statistical data always has been impact the drought monitoring in regions without enough statistical data. remote sensing can provide suitable information with high temporal and regional resouloution for vegetation and drought monitoring distribution.. In this research, rangeland drought investigation in 1386 to 1388 has been done in Iran using MODIS images with 250m resolution. The raw MODIS images were processes and geometric and radiometric corrections were performed. Then the daily NDVI (Normalized Difference Vegetation Index) was calculated as an important indicator of range land drought. Two methods are applied for NDVI analysis in country. First NDVI is classified in 4classes. Each class indicates the special level of vegetation cover. Here the area of classes for each province is analysed annually. At the next stage yearly NDVI distribution and NDVI differential maps are considered spatially. With the aim of monitoring the variation of vegetation cover with meteorological drought, standard precipitation index (SPI) was calculated in yearly analysis, general aspects of drought was detected. Considering drought of 1387 variation of vegetation cover and rainfall of next and last year are compared with 1387.the result show that precipitation and vegetation cover hasn't simultaneous performance and the time distribution of rainfall is important factor in vegetation cover and using daily satellite images for rangeland drought investigation present an integrated estimate of drought conditions especially in basins without enough statistical data.
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