Abstract
S H Sanaei-Nejad
Lecturer
Ferdowsi University of Mashhad
Mashhad, Iran
Email: [email protected]
A Abedi, K Davari
Abstract
Drought and flood are the most damaging natural hazards. However, monitoring these phenomena by traditional methods is difficult due to the insufficient number of weather stations in many parts of the world. Despite its infancy, remote sensing technology, along with geographical information system (GIS), has shown its potential use in providing in useful and timely information on drought and flood. In the present study the impact of drought on crops of a region in Khorasan Province was evaluated using two Landsat images, one taken in a dry year and the other in a fairly humid one. The evaluation was done using the NDVI index of the crops of the region. The software used in this study was Idrisi For Windows version 2. Firstly the agricultural fields were discriminated and digitized. Then the NDVI index for fields was calculated and classified into 10 classes, percent areas of which were determined. At the end a comparison was made between the percent values of two years. The comparison made it quite clear that the values of NDVI in the humid year (1987) tended to be in the range of 0.5-0.7 while in the dry year (2001) they were in the range of 0.1- 0.4. This technique can be used as a preliminary study in a drought decision support system or as a self-standing procedure for developing a NDVI archive of past years.
