نویسندگان
1 دانشجوی کارشناسی ارشد هواشناسی کشاورزی، گروه مهندسی آبیاری وآبادانی، دانشگاه تهران
2 استادیار گروه مهندسی آبیاری و آبادانی، دانشگاه تهران
3 استادیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی، گرگان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Drought affects not only agricultural productions and water resources but also the vegetation cover of a region and promotes the desertification. Investigation of drought effect on spatial and temporal variations of vegetation cover as is widely performed using drought indices derived from satellite images. The aim of this study is to find out whether it is possible to detect the changes in vegetation cover using satellite drought indices. To achieve this goal, the change vector (CV) analysis as one of the change detection algorithms, was used. In this method, the change occurred in vegetation has been attributed to the change vector. The change vector contains two components, change magnitude and change orientation. In this paper, the CV was calculated by four satellite drought indices based on the condition of vegetation, namely NDVI, NDVIA, VCI, CTVI using NOAA AVHRR images, and one ground-based drought index, namely Standardized Precipitation Index (SPI). The results showed that satellite drought indices have a high correlation in detection of the change magnitude. The highest and lowest correlation between satellite-based drought indices and the SPI were observed for NDVI and VCI, respectively.
کلیدواژهها [English]