Abstract To carry out this research, interpolated data of daily rainfall from Iran’s Asfazari data base during 1/1/1979–31/12/2013 is used. The day along with pervasive rainfall considered a day that at least 50% of Iran’s territory has received more than 1 mm for at least two consecutive days. Based on mentioned thresholds, 224 days selected for statistical analysis. The sea level pressure data, zonal and meridional wind components and specific humidity with spatial resolution of 0.25*0.25 Gaussian degree in spatial domain of 10 °N to 60 °N and 15 °E to 75 °E obtained from the European Center for Medium range Weather Forecasting (ECMWF) ERA-Interim for selected days. Then on the data matrix of sea level pressure, the cluster analysis by Ward linkage method done and 4 sea level pressure patterns with different configuration of synoptic systems were identified. The findings showed that in the sea level, the interaction between southern thermal low pressure systems (Arabia low pressure) with Europe and Siberia cold immigrant high pressure both by individual and integration and anticyclone circulation of Arab sea from the low level of 1000–500 hPa of troposphere have the most role on occurrence of durable and pervasive rainfall of Iran. The most Vertically Integrated Moisture Flux Convergence in the first layer of troposphere (1000–850 hPa) observed in low height regions, in the second layer of troposphere (775–700 hPa) on Zagros Mountains and in third layer of troposphere (600–500 hPa) is seen in mountains leeward of Iran. Also the results showed that the maximum rainfall cores has the most coordination with Vertically Integrated Moisture Flux Convergence (VIMFC) in the second layer of troposphere (775–700 hPa) on the Zagros heights in the southwest of Iran.

中文翻译：

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伊朗持久和普遍降雨期间海平面压力模式和垂直综合湿气通量收敛VIMFC的天气分析

摘要 为了开展这项研究，使用了伊朗 Asfazari 数据库在 1/1/1979-31/12/2013 期间的日降雨量插值数据。伴随着普遍降雨的这一天被认为是伊朗至少 50% 的领土至少连续两天降雨量超过 1 毫米的一天。根据上述阈值，选择 224 天进行统计分析。从欧洲中等范围中心获得的10°N至60°N和15°E至75°E空间域中空间分辨率为0.25*0.25高斯度的海平面压力数据、纬向和经向风分量和比湿度选定日期的天气预报 (ECMWF) ERA-Interim。那么在海平面气压数据矩阵上，通过 Ward 关联方法进行聚类分析，并确定了具有不同天气系统配置的 4 种海平面压力模式。研究结果表明，在海平面上，南部热低压系统（阿拉伯低压）与欧洲和西伯利亚冷移民高压通过阿拉伯海从1000-500 hPa低层的单独和整合以及反气旋环流相互作用对流层对伊朗持久和普遍降雨的发生作用最大。在低高度区域观测到的对流层第一层 (1000-850 hPa)、扎格罗斯山脉的对流层第二层 (775-700 hPa) 和对流层第三层 (600-500 hPa) 见于伊朗背风山。