The impact of El Niño–Southern Oscillation (ENSO) phase transition on the atmospheric circulations, precipitation and temperature in the Middle East (ME) during the period of 1950–2018 autumn seasons were analyzed. ENSO events were selected based on the Oceanic Nino Index (ONI) and its phase transition from El Nino to La Nina (type 1) and from La Nina to El Nino (type 2) events during the study period. Monthly and climate means of data for precipitation, temperature, geopotential height, wind components (u and v) and Sea level pressure (SLP) obtained from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. Composites of the means and anomalies were derived from selected case studies of the ENSO phase transitions. Finally, the student’s t test is used to determine the significance of the composite means in each grid point. The results show during transitions, the SLP structure over the Atlantic region changes, in a way that pressure differences between Iceland low and the Azores high during type 1 (type 2) is minimum (Maximum) and also statistically significant at 95% confidence level which, these conditions are accompanied by statistically significant enhancing (decreasing) rainfall over the most parts of the ME. In addition, the variability of upper level geopotential height and zonal wind were found over the region which lead to favorable or less favorable conditions for infiltration of planetary Rossby waves to the ME in type 2 and type 1, respectively. Also this study reveals that, moisture flux transport from the adjoining seas to the ME is extremely different in both types, so that during type 2 (type 1), the ME receives significant (insignificant) amounts of moisture. This study therefore identified that most parts of the ME experienced statistically significant positive (negative) anomalies of precipitation during type 2 and type 1 respectively.

中文翻译：

---

ENSO相变对中东秋季大气环流，降水和温度的影响

分析了厄尔尼诺-南方涛动（ENSO）相变对1950-2018年秋季季节期间中东（ME）大气环流，降水和温度的影响。在研究期间，根据海洋Nino指数（ONI）及其从El Nino到La Nina（类型1）以及从La Nina到El Nino（类型2）事件的相变来选择ENSO事件。从国家环境预测中心/国家大气研究中心（NCEP / NCAR）重新分析获得的降水，温度，地势高度，风分量（u和v）和海平面压力（SLP）的月度和气候数据。手段和异常的综合来自于ENSO相变的选定案例研究。最后，学生的t检验用于确定每个网格点中复合均值的重要性。结果表明，在过渡过程中，大西洋地区的SLP结构发生了变化，其方式为：在类型1（类型2）期间，冰岛低压和亚速尔群岛高压之间的压力差最小（最大），并且在95％的置信水平下也具有统计学意义。 ，这些条件伴随着ME大部分地区的统计显着增加（减少）降雨。此外，在该地区发现了高层地球电位高度和纬向风的变化，这分别导致了将罗斯伯波向2型和1型ME渗透的有利条件或不利条件。这项研究还表明，在两种类型中，从相邻海域到ME的湿气通量传输都极为不同，因此在2型（1型）期间，ME接收到大量（微不足道）的水分。因此，这项研究确定，ME的大多数部分分别在2型和1型期间经历了统计学上显着的正（负）降水异常。