气象科技进展
氣象科技進展
기상과기진전
Advances in Meteorological Science and Technology
2015年
3期
40-48
,共9页
中亚低涡%三维结构%扰动动能转换%罗斯贝波能量频散
中亞低渦%三維結構%擾動動能轉換%囉斯貝波能量頻散
중아저와%삼유결구%우동동능전환%라사패파능량빈산
Central Asian vortex%three-dimensional structure%eddy kinetic energy conversion%Rossby wave energy dispersion
利用NCEP/NCAR逐日再分析资料，分析了1996年7月11—22日中亚低涡持续活动发展、维持和减弱过程中三维结构及其能量转换和频散特征。结果表明：（1）中亚低涡在对流层中高层发展并向高层和低层延伸，最大正涡度中心始终位于中高层，存在300hPa以下为冷心、以上为暖心结构的气旋性深厚天气尺度系统，其发展—成熟—减弱过程最大正涡度中心由低涡中心西侧逐渐移至东侧，并对应低层辐合、中高层辐散的强上升运动。（2）扰动动能（KE）变化定量地反映中亚低涡强度变化和发展阶段，对流层中、高层KE强，同时，低涡内部的能量转换及其与外界的能量输送也主要发生在中、高层。低涡发展过程KE来源于扰动位能（AE）的转换和区域开放边界的扰动动能输入，且两者作用相当，它们使得低涡快速发展。低涡成熟期系统内部的能量转换很小，KE来自于外界扰动位能输入，消耗项为向开放边界的扰动动能输出。（3）此次低涡持续活动过程平均而言，东北大西洋反气旋式异常环流中心是罗斯贝（Rossby）波能量的频散源地，波能量向东欧—乌拉尔山频散，东欧—乌拉尔山正异常环流成为向中亚地区能量频散的“中继站”，此地重新激发罗斯贝波向中亚地区频散使得中亚低涡持续活动了12d。（4）中亚低涡不同发展阶段罗斯贝波能量频散路径有所不同。发展和稳定维持期，东北大西洋正异常环流向东欧—乌拉尔山地区的能量频散过程显著，使得东欧正异常环流强盛发展并作为能量“中继站”向中亚地区频散能量，从而导致中亚低涡快速发展和稳定维持；减弱期，东北大西洋罗斯贝波能量向东南方向频散在地中海东部地区进入亚洲副热带西风急流，然后沿亚洲急流向东频散，使得中亚低涡维持，这阶段东欧—乌拉尔山地区不再出现向中亚地区的能量频散。
利用NCEP/NCAR逐日再分析資料，分析瞭1996年7月11—22日中亞低渦持續活動髮展、維持和減弱過程中三維結構及其能量轉換和頻散特徵。結果錶明：（1）中亞低渦在對流層中高層髮展併嚮高層和低層延伸，最大正渦度中心始終位于中高層，存在300hPa以下為冷心、以上為暖心結構的氣鏇性深厚天氣呎度繫統，其髮展—成熟—減弱過程最大正渦度中心由低渦中心西側逐漸移至東側，併對應低層輻閤、中高層輻散的彊上升運動。（2）擾動動能（KE）變化定量地反映中亞低渦彊度變化和髮展階段，對流層中、高層KE彊，同時，低渦內部的能量轉換及其與外界的能量輸送也主要髮生在中、高層。低渦髮展過程KE來源于擾動位能（AE）的轉換和區域開放邊界的擾動動能輸入，且兩者作用相噹，它們使得低渦快速髮展。低渦成熟期繫統內部的能量轉換很小，KE來自于外界擾動位能輸入，消耗項為嚮開放邊界的擾動動能輸齣。（3）此次低渦持續活動過程平均而言，東北大西洋反氣鏇式異常環流中心是囉斯貝（Rossby）波能量的頻散源地，波能量嚮東歐—烏拉爾山頻散，東歐—烏拉爾山正異常環流成為嚮中亞地區能量頻散的“中繼站”，此地重新激髮囉斯貝波嚮中亞地區頻散使得中亞低渦持續活動瞭12d。（4）中亞低渦不同髮展階段囉斯貝波能量頻散路徑有所不同。髮展和穩定維持期，東北大西洋正異常環流嚮東歐—烏拉爾山地區的能量頻散過程顯著，使得東歐正異常環流彊盛髮展併作為能量“中繼站”嚮中亞地區頻散能量，從而導緻中亞低渦快速髮展和穩定維持；減弱期，東北大西洋囉斯貝波能量嚮東南方嚮頻散在地中海東部地區進入亞洲副熱帶西風急流，然後沿亞洲急流嚮東頻散，使得中亞低渦維持，這階段東歐—烏拉爾山地區不再齣現嚮中亞地區的能量頻散。
이용NCEP/NCAR축일재분석자료，분석료1996년7월11—22일중아저와지속활동발전、유지화감약과정중삼유결구급기능량전환화빈산특정。결과표명：（1）중아저와재대류층중고층발전병향고층화저층연신，최대정와도중심시종위우중고층，존재300hPa이하위랭심、이상위난심결구적기선성심후천기척도계통，기발전—성숙—감약과정최대정와도중심유저와중심서측축점이지동측，병대응저층복합、중고층복산적강상승운동。（2）우동동능（KE）변화정량지반영중아저와강도변화화발전계단，대류층중、고층KE강，동시，저와내부적능량전환급기여외계적능량수송야주요발생재중、고층。저와발전과정KE래원우우동위능（AE）적전환화구역개방변계적우동동능수입，차량자작용상당，타문사득저와쾌속발전。저와성숙기계통내부적능량전환흔소，KE래자우외계우동위능수입，소모항위향개방변계적우동동능수출。（3）차차저와지속활동과정평균이언，동북대서양반기선식이상배류중심시라사패（Rossby）파능량적빈산원지，파능량향동구—오랍이산빈산，동구—오랍이산정이상배류성위향중아지구능량빈산적“중계참”，차지중신격발라사패파향중아지구빈산사득중아저와지속활동료12d。（4）중아저와불동발전계단라사패파능량빈산로경유소불동。발전화은정유지기，동북대서양정이상배류향동구—오랍이산지구적능량빈산과정현저，사득동구정이상배류강성발전병작위능량“중계참”향중아지구빈산능량，종이도치중아저와쾌속발전화은정유지；감약기，동북대서양라사패파능량향동남방향빈산재지중해동부지구진입아주부열대서풍급류，연후연아주급류향동빈산，사득중아저와유지，저계단동구—오랍이산지구불재출현향중아지구적능량빈산。
Using the NCEP/NCAR reanalysis daily datasets, dynamic and thermal three-dimensional structure, energy cycle and Rossby wave energy dispersion of Central Asian vortex (CAV) persistent activity from July 11 to July 22 in 1996 are studied. The Results show that the vortex developed at the middle-upper ifrstly and extended upward and downward with time, which had an obvious cold core structure down 300 hPa and a warm core structure over 300 hPa along with maximal positive vorticity at the middle-upper troposphere. During its development - mature - weakened process, maximal positive vorticity moved eastward from westside of vortex center. At the same time its upper-level strong divergence, lower-level convergence and upward motion area moved eastward. Eddy kinetic energy (KE) variation can quantitatively manifest intensiifcation change and developing stages of vortex; in the meantimeKE is quite strong at the middle and upper tropospheres. Energy conversion within vortex and energy transportation with environment mostly take place over 700 hPa. The conversion term from eddy available potential energy (AE) toKEand eddy kinetic energy inlfow from open atmospheric region boundaries act as main sources of theKE, and they play an equivalent role which bring about a rapid development of vortex. It keeps weak energy conversions within vortex during its mature stage, and the source and sink ofKE is respectively eddy available potential energy import from environment and eddy kinetic energy outlfow. For middle-range process of this vortex, the anti-cyclone anomaly center over Northeast Atlantic is the fountain of Rossby wave energy dispersion with Rossby wave propagating from Northeast Atlantic to East Europe—Urals (EAU). So the positive height anomaly circulation over EAU acts as “relay station” of energy dispersion for Central Asia. The Rossby wave emanates again from EAU and propagates to Central Asia, causing CAV persistent activity for 12 days. The characteristics of Rossby wave propagation, however, are signiifcantly different in different periods of CAV. During developing and maintaining periods, the anti-cyclone anomaly center over Northeast Atlantic and strong wave lfux divergence process are prominent and cause the positive height anomaly circulation over East Europe to develope, which acts as a "relay station" of energy and continues to propagate energy for Central Asia, consequently bringing about CAV sudden development and stable maintenance. During the weakening period, Rossby waves propagate from Northeast Atlantic to the east of the Mediterranean Sea and enter Asia subtropical jet stream to continue dispersion along with the jet stream. It is not found that Rossby wave propagates from the EAU to Central Asia.
