Evaluation of meteorological indices of draught versus remote sensing indices: A case study of Yazd province

Drought has occurred as a natural disaster and an inevitable phenomenon across many parts of the world, especially in arid areas for a long time. To monitor draughts and to determine their extent and indices, meteorological data, such as those obtained from precipitation, can be of use. In the absence of these data, techniques of remote sensing are useful tools in monitoring droughts. The city of Yazd located in the central plateau of Iran is surrounded by deserts, and the deserts have a great impact on the occurrence of severe droughts in the region. The present study is based on the data obtained from 25 synoptic stations in Yazd province within a 20-year period (1990-2010) to determine the weather SPI and the RDI index in long series in 3, 6 and 18 months. For this purpose, satellite images were used in the form of bands of MODIS images from 2000 to 2010 to assess the remote sensing parameters of VCI and LST. After interpolation of the meteorological indices, the correlation between them was investigated. As the results show, the correlation was relatively low. Therefore, to verify the initial results, the calculation of the correlation indicates was repeated using the station points. The final results showed a good correlation so as for SPI and VCI to be found approximately 0.5 to 61.3 % and for RDI and LST to be between 25.7 and 82.1 respectively. Based on the results, distance sensing indices can be appropriate alternatives for meteorological indices in drought studies.