In this study, the total seasonal and annual frequency of dust storm days (DSD) of 44 synoptic stations with long-term statistics over a 50-year period from 1968 to 2017 was analyzed using the Mann–Kendall nonparametric test, kriging, and radial basis function (RBF), spatial interpolation methods, directional distribution of spatial statistics, and mean center. Based on the results of Mann–Kendall test and related maps using RBF, it was found that about 30 stations had an increasing trend, most of which demonstrated a significant upward trend in the southern regions and western part of Iran. Significant decreasing trends were observed in the northern part. The results of DSD zoning showed that the maximum incidence of DSD occurs in spring and summer, and more in the southern and western parts of Iran, while they are much less frequent in the middle and northern regions of Iran. Investigation of the directional distribution of spatial statistics and the decadal foci for five decades, i.e., 1968–1977, 1978–1987, 1988–1997, 1998–2007, and 2007–2017, showed that the foci of DSD in the first and second decades moved to the east, but subsequently shifted to the west in the fourth and fifth decades. Given that the movement has been to the west, it can be said that the frequency of DSD is increasing from southeast to west. The results of directional distribution also showed that in all seasonal and annual time scales, the focus of DSD in Iran is from southeast to west.

在这项研究中，使用 Mann-Kendall 非参数检验、克里金法和径向分析法分析了 1968 年至 2017 年 50 年间长期统计的 44 个天气站的沙尘暴日 (DSD) 的季节性和年度总频率。基函数 (RBF)、空间插值方法、空间统计的方向分布和平均中心。根据Mann-Kendall检验结果和RBF相关地图发现，约有30个站点呈上升趋势，其中大部分在伊朗南部地区和西部地区呈显着上升趋势。在北部观察到显着的下降趋势。DSD区划结果表明，DSD的发病率最高发生在春季和夏季，伊朗南部和西部地区发病率较高，伊朗中部和北部地区发病率较低。对 1968-1977、1978-1987、1988-1997、1998-2007 和 2007-2017 五个十年空间统计方向分布和年代际焦点的调查表明，DSD 的焦点在第一和第二几十年向东移动，但随后在第四和第五个十年向西移动。鉴于运动一直向西，可以说DSD的频率从东南向西增加。定向分布的结果还表明，在所有季节和年度时间尺度上，伊朗DSD的重点是从东南向西。