2016年夏季内蒙古降水与环流异常特征分析

Analysis of Precipitation in Inner Mongolia and Circulation Anomaly Characteristics in Summer of 2016

文章利用2016年前期海洋表面温度异常信号与夏季及各月阻塞高压、东北冷涡、西太平洋副热带高压、夏季风强度等环流系统关系,分析了夏季内蒙古降水异常成因和预测检验。结果表明:(1)2016年夏季500hPa欧亚中高纬高度场纬向呈"+-+"的分布,乌拉尔山和鄂霍次克海阻塞高压强,夏季风弱,同时西太平洋副热带高压位置偏南,东北冷涡强度阶段性变化,导致内蒙古降水略少,初夏与盛夏出现多雨少雨转折。(2)初夏6月,内蒙古异常降水主要为阻塞高压和东北冷涡影响;盛夏7、8月夏季风、副热带高压强度、脊线位置、阻塞高压等系统不同配置对内蒙古降水影响较大。(3)前期赤道太平洋Nino区海温指数及大西洋三极子指数(NAT)与夏季风、中高纬度环流与阻塞高压、西太平洋副热带高压等关系及对降水异常影响显著。

The causes and predictive test of precipitation anomalies in Inner Mongolia in summer of 2016 had been analyzed by using the relationship between sea surface temperature anomaly signals in early 2016 and the summer and monthly blocking high,northeast cold vortex,western Pacific subtropical high,and summer monsoon intensity.The results shows that the distribution of 500 hPa Eurasian mid-high latitude height field was"+-+"in the summer of 2016.The Ural Mountains and the Okhotsk Sea had strong blocking high pressures.The summer winds were weak.At the same time,the western Pacific subtropical highs were located southward,and the northeast cold vortex intensity changed in stages.The above reasons lead to a little less precipitation in Inner Mongolia,and there were rainy transitions in early summer and midsummer.,The abnormal precipitation in early summer in Inner Mongolia was mainly caused by blocking high pressure and northeast cold vortex.The different configurations of summer wind,sub-high intensity,ridge line position and resistance height had great influence on precipitation in July and August of summer.The relationships between the early SST equatorial Pacific Nino temperature index,the Atlantic three-level sub-index(NAT),summer monsoon,mid-high latitude circulation and obstruction,and western Pacific subtropical high had significant effects on precipitation anomalies.