Zoning Climatic Drought and Drought Magnitude Using SPI Index and Kirijing Geostatistical Method (Case Study: Kerman Province)

Document Type : Original Article

Authors

1 Watershed management, Natural resources, University of Sari Agriculture science and Natural Resources, sari iran

2 Professor of Sari Agricultural Science and Natural Resources.Department of rang and watershed managemen

Abstract

Drought occurs in all climatic zones including areas with low and high rainfall. It is related to amount of rainfall decrease in a long time period such as a season or year. Dryness is one of the permanent features of climatic zones with low rainfall, but the drought is a temporary disturbance. One of the areas severely affected by drought in recent years is Kerman Province. This fact reveals need to carry out extensive research in this area. In this study, the standardized precipitation index (SPI) was applied in order to the drought zoning in Kerman province. After collecting data from 59 stations including synoptic and rain-gauge in the province from 1974 to 2004 and removing incomplete statistics, the SPI index computed in scales 1, 3, 6, 9 and 12 months. Evaluation of different interpolation methods for drought zoning using Geographic Information System (GIS) showed that Kriging method is suitable for interpolation of the drought severity. Therefore, using this method and by applying GS + software, local values of SPI index used for drought periods monitoring were extended to the areal values. We have produced maps of intensity and the same value magnitude with determination a period of dry in stations in time scale. The results showed that have more sensitivity for drought accurence a portion of west souther and west earas of kerman province, located in baft, sirjan and rabor towns. Whatever time scale goes higher then, absolute related with dryness periods get more.

Keywords