摘要
利用NCEP/NCAR 1°×1°再分析资料、历史天气图、青藏高原低涡切变线年鉴,分析了1998-2013年持续高原涡诱发西南涡结伴而行的观测事实,并对一例持续高原涡诱发西南涡的长时间伴行过程进行天气、诊断分析。结果表明,在持续高原涡与西南涡共同活动过程中,两涡移向较一致的多数是由持续高原涡诱发的西南涡过程造成的,它们的移向多为向东或东北移;持续高原涡诱发的西南涡是在500h Pa上东亚环流经向度减弱,在处在切变流场中的高原涡的环流东南部-西南气流下空生成的;伴行的西南涡受高原涡活动影响大,高原涡加强会影响西南涡加强;高原涡对西南涡的诱发作用是由高原涡移出高原,其伴随的正涡度向下伸,与对流层低层盆地内气流的气旋性弯曲所伴的正涡度叠合,使盆地内气旋性涡度加强而诱发西南涡生成的,西南涡区上空正涡度平流随高度增加的强迫上升作用是高原涡诱发西南涡的又一重要因素;高原涡与西南涡伴行是与高原涡区、西南涡区的正涡度平流及高原涡区、盆地涡区上空正涡度平流随高度增加的强迫上升作用密切相关的。
By using NCEP/NCAR FNL reanalysis data, historical weather graphs and Qinghai-Tibetan Plateau and shear line year books, the observational facts of sustained departure Qinghai-Tibetan Plateau Vortex （SDPV） accompanying with influenced Southwest Vortex （SWV） during year 1998 to 2013 were analyzed, and a long time lasting case study of SDPV with induced SWV was analyzed by using synoptic and diagnostic methods. The results show that the SDPV and SWV moving in same direction is mainly caused by the SWV, which is induced and controlled by SDPV, and their main moving direction is east or north-east in the joint active processes of them. The SWV induced by SDPV generated under the south-west air flow in the southeastern portion of the SD- PV circulation on 500 hPa, with weaker air flow along longitude side. The SWV accompanying with the SDPV will be stronger while the SDPV is stronger and be influenced largely by the SDPV. When SDPV is mo~,ing out of the Plateau, the positive vorticity air flow is downward to lower level and to be superposition with the low troposphere positive vorticity region which is going with cyclonic bend, and this will strengthen the cyclonic vor- ticity and thus generates the SWV. The force rising effect of the positive vorticity advection along with the alti- tude over the southwest vortex area is another important factor of the SWV induced by the SDPV. The accompan- ying between SDPV and SWV is closely related to the plateau vortex area, the positive vorticity advection of the southwest vortex area and the plateau vortex area, and the positive vorticity advection along the basin vortex area.
出处
《高原气象》
CSCD
北大核心
2018年第1期54-67,共14页
Plateau Meteorology
基金
国家自然科学基金项目(41275052,91332715)
国家重点基础研究发展973计划项目(2012CB417202)
关键词
高原涡
西南涡
诱发
环境场
成因
Plateau Vortex
Southwest Vortex
induced
environmental field
causes
