Study of dispersion high and low rainfall patterns in the Northwest of Iran

The most intractable climate parameters are precipitation Change and variability in precipitation studies are really significant, and they have an important role in climate prediction In order to review low and high rainfall patterns, a data base of rainfall has been formed initially in the northwest of Iran. Then a 30-year period, monthly, were selected for the present study from 1984 to 2014, and cells dimension of 10 × 10 km were created in study area. The modern methods of spatial statistics such as spatial autocorrelation global Moran and hot spots were used in order to achieve changes of seasonal precipitation in the northwest by GIS software. The results of this study showed that the spatial distribution of rainfall in northwest of Iran has a high cluster pattern. In the meantime, according to global Moran index and hot spots, precipitation patterns has a positive spatial autocorrelation pattern (high rainfall pattern) in the northwest and northwest, west and southwest region, and parts of the northeast, northwest and southwest region has a negative spatial autocorrelation (low rainfall pattern). In most cases during the study period, a large part of the region, almost half of the total studied area had no significant pattern of spatial autocorrelation.