CAJ | 학술논문

中亚低涡是中期时间尺度（4天以上）的对流层深厚切断低压系统，也是造成新疆暴雨（雪）、持续低温天气的重要影响系统之一，对其形成、维持和减弱的能量特征还不十分清楚。利用美国国家环境预报中心／国家大气研究中心（NCEP／NCAR）2．5°×2．5°逐日再分析资料和有限区域能量循环方程，对1996年7月10-20日造成新疆区域两次暴雨过程的中亚低涡系统进行分析，以揭示低涡持续活动11天的能量循环和转换特征。分析结果表明，中亚低涡活动具有明显的阶段性能量学特征。这次低涡发展和减弱过程处于斜压不稳定状态，扰动动能来源于扰动位能的转换和区域开放边界扰动动能的输入，且两者作用相当，它们使得低涡快速发展，同时区域内部非绝热加热制造的一部分扰动有效位能向外输出，在减弱期扰动有效位能向外输出大于扰动位能的转换和区域开放边界扰动动能的输入，因此低涡逐渐减弱。低涡成熟期处于正压不稳定状态，系统内部的能量转换很小，扰动动能来自于外界扰动位能输入，支出项为向开放边界的扰动动能输出。低涡过程各个时期纬向平均动能向扰动动能的转换都很小，即正压不稳定造成的能量转换较弱。低涡活动过程中，在对流层中、高层扰动动能很强，表明中亚低涡是主要在对流层中、高层活动的天气尺度系统，低涡内部的能量转换及其与外界的能量输送主要发生在中、高层，扰动位能和扰动动能的变化很好地反映低涡的强度变化和发展阶段，且能量的垂直输送对低涡系统的发展也有一定促进作用。
중아저와시중기시간척도（4천이상）적대류층심후절단저압계통，야시조성신강폭우（설）、지속저온천기적중요영향계통지일，대기형성、유지화감약적능량특정환불십분청초。이용미국국가배경예보중심／국가대기연구중심（NCEP／NCAR）2．5°×2．5°축일재분석자료화유한구역능량순배방정，대1996년7월10-20일조성신강구역량차폭우과정적중아저와계통진행분석，이게시저와지속활동11천적능량순배화전환특정。분석결과표명，중아저와활동구유명현적계단성능량학특정。저차저와발전화감약과정처우사압불은정상태，우동동능래원우우동위능적전환화구역개방변계우동동능적수입，차량자작용상당，타문사득저와쾌속발전，동시구역내부비절열가열제조적일부분우동유효위능향외수출，재감약기우동유효위능향외수출대우우동위능적전환화구역개방변계우동동능적수입，인차저와축점감약。저와성숙기처우정압불은정상태，계통내부적능량전환흔소，우동동능래자우외계우동위능수입，지출항위향개방변계적우동동능수출。저와과정각개시기위향평균동능향우동동능적전환도흔소，즉정압불은정조성적능량전환교약。저와활동과정중，재대류층중、고층우동동능흔강，표명중아저와시주요재대류층중、고층활동적천기척도계통，저와내부적능량전환급기여외계적능량수송주요발생재중、고층，우동위능화우동동능적변화흔호지반영저와적강도변화화발전계단，차능량적수직수송대저와계통적발전야유일정촉진작용。
A Central Asian vortex (CAV)of medium-range time scale (over 4 days)is a deep cutoff low in the troposphere, and it is also one of the important influence systems which cause rainstorm,snowstorm and persisting low-temperature in the Xinjiang region.But the energetic characteristics at its formation,maintenance and mature stage are not clear.Energetic char-acteristics of the medium-range process of CAV during 10-20 July 1996,which caused 2 rainstorm processes in Xinjiang,are investigated using the NCAR/NCEP daily 2.5°×2.5°reanalysis data and the energy cycle equations for open atmospheric re-gion.The results show that distinct features exist for the different periods.This vortex is always getting along with baroclinic instability conditions during either the developing and weakening process.The conversion term from eddy available potential en-ergy (AE )to eddy kinetic energy (KE )and the eddy kinetic energy inflow (BKE )from open atmospheric region boundaries act as main sources of the KE ,and they play an equivalent role in bring about the rapid development of vortex,and at the same time a part of eddy available potential energy by the diabatic heating (RE )exports.Since RE is more than AE→KE and BKE ,it causes vortex to weaken during the weakening stage.The vortex keeps barotropic instability conditions with weak energy con-versions within vortex during its mature stage,and the source and sink of KE is eddy available potential energy import from en-vironment and eddy kinetic energy outflow,respectively.During the every stages the conversion term from the zonal kinetic energy (KZ )to KE is very weak,suggesting that energy conversion from barotropic instability is rather little.KE is quite strong at the middle and upper troposphere,implying that the Central Asian vortex mainly exists about over 700 hPa.Energy conversion within the vortex and energy transportation with environment mostly take place over 700 hPa.AE and KE variation can primely manifest intensity change and the developing stage of vortex.Energy vertical transportation promotes the vortex development to a certain degree.