Analysis of drought and wet period climatic in the basin Dareh Rood Ardabil Using spatial autocorrelation statistics

In the present study to identify and analyze the drought and rain in the catchment area of river valley in North West Iran, were used The annual rainfall data of 38 stations for Climatology and synoptic during a period of 25 years (1990-1991 to 2014-2015). Initially, the use of SPI gamma index, as well as the Deciles drought index, were identified drought and wet periods in the study area. Stations studied In terms of homogeneity Using Agglomerative hierarchical clustering (AHC) method in three homogeneous classes. In the following Drought results with simple Kriging method, with a Semi-Variogram Spherical model with the lowest RMS erro, Zoned in ArcGIS software. Using appropriate variogram, cells with dimensions of 1 * 1 km were extended to perform spatial analysis on the study area. In order to explain the pattern of drought in the region From Global and local statistics of Moran were used as spatial data exploration approaches. The results of the application of Moran's index about identifying spatial distribution of drought patterns showed that The values of the different years during the period, have a positive a positive coefficient close to 1 (Moran's I> 0.95) and this shows that The spatial distribution of drought is clustered. Also the results of the standard score Z values and the P-Value proved the clustering of spatial distribution of drought. Eventually from General Statistics G Was used to identify spatial patterns of the drought. The results showed that the east and north-east of the region have a very severe drought pattern whose significance level is 0.99