摘要
利用NCEP再分析资料对1981年8月15日～9月9日发生在陕西的一次持续性暴雨的大尺度环流特征和物理量场进行分析。结果表明:欧亚中高纬度环流形势呈稳定的"L"型,副热带高压偏北偏西偏强是造成持续性暴雨的直接原因;低纬度热带气旋活跃并有较长的生命史有利于中纬度环流形势的稳定维持,热带气旋外围暖湿气流、强盛的印度季风与西太平洋副热带高压外围暖湿气流相结合为暴雨提供了持续的水汽和能量;持续性暴雨期间高空西风急流与副热带东风急流稳定并存;暴雨发生在南亚高压的辐散区与高空急流入口区右侧的辐散叠置区域,高空急流不断带来干冷空气向下入侵,叠加在暴雨区的低层的暖湿气流上,加大了暴雨区的大气层结不稳定,有利于深对流的发生。
Based on the NCEP reanalysis data,the large-scale circulation features and physical quantity field of a continuous rainstorm occurred in Shaanxi from August 15 to September 9,1981 were analyzed.As indicated by the results,the middle and high latitude circulation of Eurasia was stable ＂L＂ type,the northerly westerly and stronger subtropical high was the direct cause of this continuous rainstorm;the active and long live low-latitude tropical cyclone activity was conducive to the stable maintenance of mid-latitude circulation.Warm air outside the tropical cyclone,strong Indian monsoon and the warm air outside the West Pacific subtropical high rainfall combined to provide continuous water vapour and energy;high-latitude westerly jet and subtropical easterly jet stably existed,heavy rain occurred in overly area of the South Asia high divergence and the divergence at the right of upper level jet stream entrance area,the jet stream which bringed constantly cold air invaded downward,superimposing on the low-level warm air of the storm zone,which increased the instability of atmospheric stratification of the storm zone and was conducive to the occurrence of deep convection.
出处
《安徽农业科学》
CAS
北大核心
2011年第11期6566-6570,共5页
Journal of Anhui Agricultural Sciences
关键词
持续性暴雨
台风
急流
西北地区东部
Continuous rainstorm
Typhoon
Jet stream
Eastern part of Northwest China
