%0 Journal Article
%T A Study of the Forming Characteristics of Blocking High in Northern Asia during the Flood Period of the Huaihe River Basin in 2003<br>2003年淮河大水期间亚洲北部阻塞高压的形成特征
%A LI Feng
%A DING Yi-Hui
%A BAO Yuan-Yuan
%A <br>李峰
%A 丁一汇
%A 鲍媛媛
%J 大气科学
%D 2008
%I 
%X Summer blocking anticyclones are studied to probe into their activity mechanism by using NCEP daily reanalysis dataset and observation data during the flood period of the Huaihe River basin in 2003.The energy and dynamical diagnosis along with some statistic methods such as spectrum decompose,filter are widely used to investigate this subject.Especially,spectrum energy equation is introduced into this work.The results show that interaction of wave and flow is remarkable for the establishment and maintenance of the northern Asia blocking high during 2003 Meiyu period.Synoptic-scale waves are active over the upriver region,transient eddy kinetic energy is generated ceaselessly in European baroclinic zone,and it transforms into blocking mean flow energy in some preferred area in earlier June in more detail,transient eddy transport low potential vorticity(PV) air from low latitudes to blocking area continuously,which is propitious to blocking event.By contraries,mean flow weakens disturbed eddy PV function,which dissipates the blocking stream foundation and maintenance.In fact transient eddy is stronger than mean flow in the prophase that the blocking high forms according to study.The two are equivalent during the maintenance of the blocking high,and the transient eddy gets stronger than mean flow and it shifts westward,which leads low PV to evolve westward,thus the blocking body moves westward in the sixth pentad of June.Properly,wave-wave interaction is also important for the blocking high activity.It is considered as a key factor of the establishment and maintenance of the blocking high during 2003 Mei-yu period that wavenumber-1 and wavenumber-5 interacted in some area according to this research.Synchronously,synoptic-scale waves were also crucial.The interaction among the waves indicates that the longer waves got disturbance kinetic energy from mean kinetic energy transformation when blocking anticyclone began to establish and maintain in June 2003,especially,wavenumber-5 may attained energy not only by baroclinic energy transform,but also by nonlinear effect that some shorter or longer waves provided energy for it.The process is very complex and it is reverse while the blocking high trends to decay. In conclusion,the blocking activities mechanism is complicated,which includes wave-wave interaction ane wave-flow interaction,in 2003,wavenumber-5 and wavenumber-1 interacted evidently,the synoptic-scale wave worked as a trigger,but it is not aptotic,perhaps other wavenumbers are more important in other cases,further work will be continued.
%K the Huaihe River basin flood
%K blocking high
%K activity mechanism<br>淮河大水
%K 阻塞高压
%K 形成机制
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=28A2F569B2458C17&jid=46874A5A102033D774D00D819E91CD68&aid=16D840C63C82381807A0950BEEE6F578&yid=67289AFF6305E306&vid=9971A5E270697F23&iid=38B194292C032A66&sid=8F2250DA83AF77B8&eid=03436AC72A659ACA&journal_id=1006-9895&journal_name=大气科学&referenced_num=2&reference_num=26