This study examines the NCEP (National Centers for Environmental Prediction)/NCAR (National Center for Atmospheric Research) reanalysis model datasets to display the existence of the anomaly periodic time with the significant atmospheric changes in Iran. Datasets such as surface air temperatures, relative humidity, surface soil moisture, precipitation rate, mean sea level pressure, 500 hPa geopotential height, near-surface vorticity and surface scale winds have been used. The anomalies’ departures from climate normal for the meteorological datasets are investigated, and synoptically patterns have been analysed. The yearly seasonal mean surface air temperature time series during 1948–2018 displays a dramatic warming shift with an abnormal pattern in Iran from 1994 onwards. The analysis of the other datasets resulted from ERA-Interim and MERRA-2 database also confirm a warming shift nearly from 1994 over Iran. The statistical analysis of t-tests shows the existence of a significant difference in seasonal mean surface air temperatures during the anomaly period (1994–2018) and the mean values during climatology normal periodic time (1981–2010). This suggests remarkable warming over all parts of Iran with the highest changes in surface temperatures ranging ~0.1–1 °C in spring and the lowest change in fall ranging ~0.1–0.7 °C. Significant changes have resulted in precipitation rate, atmospheric humidity, soil moistures and surface wind speeds. Also, due to the strengthened northern high-pressure system along with the intensification of the 500 hPa ridge and less atmospheric humidity, a rather stable, warmer and drier atmosphere with less precipitation (respect to climate normal) over the most part of Iran has been indicated. The low-level vorticity anomalies have displayed the intensified flows from the regional desert areas to the central and north-east of Iran and from Iraq to the west and south-west of Iran for all seasons (with the higher gradient in summer rather than other seasons). Also, mean sea level pressure anomalies have exposed the increase in pressure gradient mostly over the western and central parts in all seasons except winter (with decreased wind speeds leads to haze or accumulated pollutants). This may cause instability in these parts with the possibility of frequent dust storm because of wind acceleration and warmer and dry atmospheric conditions rather normal mean. However, this study shows that during the fall seasons, humidity and precipitation values in the south-west and south-east area have been increased in comparison with the normal mean values. The increase in relative humidity during fall in the south-east areas can be associated with the impact of the intensified south-easterly flows (southern low-pressure tongue). This is accompanying by rather warmer sea surface temperatures in the southern marine areas, especially in the Oman sea and the northern Indian Ocean. Overall, this study presents some synoptic abnormal patterns associated with the recent Iran significant atmospheric climate changes.

这项研究检查了NCEP（国家环境预测中心）/ NCAR（国家大气研究中心）的再分析模型数据集，以显示伊朗大气周期发生明显变化的异常周期时间的存在。已经使用了诸如地面空气温度，相对湿度，地面土壤湿度，降水率，平均海平面压力，500 hPa地势高度，近地表涡度和地表风等数据集。对气象数据集的异常距气候正常值的偏离进行了调查，并分析了天气模式。从1948年至2018年，伊朗的年度季节性平均地面气温时间序列显示出剧烈的变暖趋势，从1994年开始，伊朗出现异常模式。对来自ERA-Interim和MERRA-2数据库的其他数据集的分析也证实了自1994年以来伊朗发生的暖化转变。的统计分析Ť试验表明，异常时期（1994-2018年）的季节平均地面气温与气候学正常周期时间（1981-2010年）的平均值存在显着差异。这表明伊朗各地显着变暖，春季的地表温度变化最高，约为0.1–1°C，秋季的最低变化为〜0.1–0.7°C。重大变化导致了降水率，大气湿度，土壤湿度和地表风速。此外，由于北部高压系统的加强以及500 hPa脊的增强和较低的大气湿度，伊朗大部分地区已经形成了相当稳定，温暖和干燥的大气，且降水量少（相对于气候正常）。表明的。低水平的涡度异常显示，所有季节从区域沙漠地区流向伊朗中部和东北部以及从伊拉克流向伊朗西部和西南部的流量都在增加（夏季梯度较高，而其他季节则较小）。季节）。同样，平均水平的气压异常暴露了除冬季以外的所有季节，西部和中部大部分地区的压力梯度增加（冬季风速降低导致霾或污染物累积）。这可能会导致这些部件不稳定，并可能由于风速加速以及较温暖和干燥的大气条件（通常为平均值）而引起频繁的沙尘暴。但是，这项研究表明，在秋季，与正常平均值相比，西南和东南地区的湿度和降水量有所增加。东南地区秋季降雨期间相对湿度的增加可能与东南气流（南低压舌头）加剧的影响有关。在南部海洋地区，特别是在阿曼海和北部印度洋，海面温度也随之升高。总的来说，这项研究提出了一些与近期伊朗重大的大气气候变化有关的天气异常模式。在南部海洋地区，特别是在阿曼海和北部印度洋，海面温度也随之升高。总的来说，这项研究提出了一些与近期伊朗重大的大气气候变化有关的天气异常模式。在南部海洋地区，特别是在阿曼海和北部印度洋，海面温度也随之升高。总的来说，这项研究提出了一些与近期伊朗重大的大气气候变化有关的天气异常模式。