1、Clustering of Tibetan Plateau Vortices by 10-30-day ISO可造成持續性強降水的高原低渦群發效應與大氣1030天低頻振蕩的聯系1. Introduction 1.1 Tibetan Plateau Vortex (TPV)Characteristics: Sub-synoptic or meso-scale convective systems at 500hPa; horizontal scale of several hundred kilometers; (Gao et al. 1981; Tao and Ding 1981)Contri

2、buting factors: topography, low-level convergence, surface sensible heating, latent heat release, etc. (e.g., DellOsso and Chen 1986; Gao 2000; Li et al. 2002; Shen et al. 1986; Shi et al. 2008; Sugimoto and Ueno 2010; Wang 1987)Tibetan Plateau Vortex (TPV) Influences: 青藏高原獨特的地理環境造就的高原特色天氣系統。TPV的活動不

3、僅影響高原地區，還東移影響我國高原下游廣大地區。夏季：暴雨洪澇,泥石流、滑坡；冬季：暴雪，雨雪冰凍。 The primary factors for local (TP) precipitation (e.g., TP Meteor. Workshop 1981);Extreme rainfall events in the East Asia (e.g., Rui et al. 1987; Tao and Ding 1981; Wang and Orlanski 1987; Wang et al. 2005);For example, the heavy rainfall and sever

4、e flooding in 1998 over the Yangtze-River basin (Shi et al. 2008; Yasunari and Miwa 2006; Yu 2001).高原渦與西南渦的區別（TPV VS SWV）高原類低渦低渦名稱高原渦（廣義）西南渦高原東坡渦（狹義）西南渦水平尺度直徑（km）-中尺度，300500-中尺度，300500-中尺度，300500生命史和活躍期3d，68月2d，57月3000100030001000定渦標準500 hPa等壓面上，高原地區形成閉合等高線的低壓或有3個站點風向呈氣旋性的低渦環流700hPa等壓面上，青藏高原東麓背風坡特定地

5、區（100110E，2535N）出現的閉合氣旋式低渦環流移出比25%左右移出高原（東移過102E）20%左右移出源地TPV的天氣影響高原渦天氣影響的常態：中尺度，生命史一般3天，區域性短期暴雨，對流性短時天氣高原渦對持續性暴雨的作用（異常影響）（1）影響方式：1）長生命史或持續性活動（停滯：西太副高、臺風）的TPV（不多見）2）高原渦與西南渦（SWV）耦合加強3）TPV的群發效應（2）影響機理：延時、增幅、擴面TPV對1998長江持續性暴雨的作用（補充天氣圖、衛星云圖展示的高原渦東移過程？）1998年，長江流域發生自1954年以來的最大洪水，宜昌出現八次大洪峰，其中有一半以上與高原低渦、切變線

6、東移密切相關，即長江上游暴雨、高原天氣系統與四川云團的活動對 年長江洪峰的形成有直接影響（TPV的“五峰暴雨”，郁淑華，2000）。對形成1998年長江上游八次洪峰的有關強降雨天氣過程的影響天氣系統分析表明：生成在青藏高原東部在四川盆地發展的低渦及與其相連的切變線是1998暴雨產生的主要天氣系統;暴雨的加強與中低緯度系統相互作用、高原渦的特殊結構密切相關（楊克明、畢寶貴等，2001）。1998年長江上游暴雨偏多與該年夏季西南低渦活動偏多有關（陳忠明等，2003）1.2 Clustering of TP vorticesTPVs Exhibit apparently active and sup

7、pressed periods (Luo et al. 1994) TPVs continuously generate within several days Clustering (Sun and Chen 1994)Previous studies:Clustering is primarily modulated by the 30-60-day intraseasonal oscillation (ISO) over the TP (Sun and Chen 1994; Zhang et al. 1991)Submonthly (10-30-day or 10-20-day) ISO

8、Submonthly Intraseanal oscillation (ISO) can also modulate convective activities over the TP (Fujinami and Yasunari 2004; Yasunari and Miwa 2006) Our result show that: TPV better matches the 10-30-day oscillation than the 30-60-day one in 1998! 1.3 Data and methodData:Station observation: Twice-dail

9、y (00, 12)GMS-5 TBB: Daily meanCFSR, ERA, NCEP1: Daily meanTime: May - Sep in 1998Method: Bandpass filterComposite Ensemble 2. Tibetan Plateau Vortices activity in 1998 SummerFig.1 Daily occurrence numbers (bar chart) and the clustering periods (gray shaded) from twice-daily synoptic mapsTP vortex d

10、efinition: A closed low pressure on 500-hPa (lower troposphere over TP) synoptic weather maps or a cyclonic circulation observed by at least 3 meteorological stations (青藏高原氣象科學研究拉薩會戰組，1981)Clustering periods: Persist for at least three continuous days;vortices number in a given period is at least fo

11、ur; Temporal interval between two vortices should not be greater than 1 day.(Sun and chen 1994)80% of total vortices occurring in clustering periods青藏高原低渦群發期的定義：(1)低渦群發期不少于三天；(2)低渦出現次數不少于5個頻次；(3)兩次低渦過程間隔期不超過一天。1998年夏季高原低渦的9個群發期3. Relationship between ISOs and clustering periods 月份低渦群發期5812日6210日；253

12、0日7410日；2124日815日；1114日；1719日；2629日Large-scale background circulation at 500hPaFig.2 Locations of TP vortices (C) ; shaded is composite GMS-5 TBB (Unit: K); 2500m of topography (dashed line).May-August averageComposite stream line in clustering periodsConvergent and convective regionFig.3 Nine clust

13、ering periods (gray shaded) and the ensemble time series of ISOs of 500-hPa relative vorticity (10-5 s-1); standard error (blue shaded) of CFSR, ERA-40 and NCEP. Regional average of (29-36N, 85-100E) TPV的9個群發期 VS ISO所有9個群發期均對應10-30-day ISO 的正位相期；其中6個對應30-60-day ISO的正位相期Temporal evolution of 10-30-da

14、y ISO10-30-day in relative vorticity (shaded is positive)TP vortices C. Zonal (ave 29-36N) Meridional (ave 85-100E) clustering periods4. Mechanism linking 10-30-day ISO and clustering of TP Vortices Phase composite 1st phase2nd (positive) phase300hPa500hPa8 TP Vortices in Phase 1 (18%)29 in Phase 2

15、(64%)High CAPEHorizontal Wind (vector in upper and lower, m/s)Equivalent potential temperature (Theta-se, red contour, K)Vertical velocity (Omega, blue-green shaded, Pa s-1)Divergence of moisture flux (blue-red shaded, 10-5 g hPa-1 cm-2 s-1)Gray shaded in middle and contour in upper and lower are Ti

16、betan Plateau.CAPE realseTPV群發與10-30d ISO的物理聯系the large-scale convergence of moisture advection through the southwest of TP connecting to the Indian monsoon activity lead to the high moist static energy accumulation at the lower troposphere over TP. The low-level convergence excites deep convective

17、systems over the central-eastern TP. The latent heat release of the deep convection can enhance the upward motion through convection-circulation feedback. The moisture supply through the southeast(SE LLJ) of TP further ensures the persistence of convective disturbances.3rd phase4th (negative) phase3

18、00hPa500hPaHorizontal Wind (vector in upper and lower, m/s)Equivalent potential temperature (Theta-se, red contour, K)Vertical velocity (Omega, blue-green shaded, Pa s-1)Divergence of moisture flux (blue-red shaded, 10-5 g hPa-1 cm-2 s-1)Gray shaded in middle and contour in upper and lower are Tibet

19、an Plateau.6 TP Vortices in Phase 3 (13%)2 in Phase 4 (4%)5. Concluding remarksOccurrences of TPV exhibit obvious active and quiescent periods. Nine clustering periods in 1998 summerNine Clustering periods (3-6day，related to persistent heavy rain)80% TPVs are occurring in those periods All (6) clust

20、ering periods are occurring in active phases of 10-30-day (30-60-day)ISO.In 10-30-day scale, high moist static energy accumulation at the lower troposphere over TP by southerly.Latent heat release of the deep convection in TP vortices systems can enhance the upward motion through convection-circulat

21、ion feedback.10-30天季節內振蕩對高原低渦群發性的調制作用利用每天2次500hPa天氣圖、多種再分析資料和衛星反演的亮溫資料，研究了1998年5-9月青藏高原低渦與10-30天季節內振蕩的關系。研究揭示出活躍期與非活躍期的高原低渦存在顯著差異。 1998年高原低渦有9個活躍期，高原低渦的群發與氣旋式環流聯系的500hPa渦度場的季節內振蕩有關。夏季高原低渦的群發現象明顯受10-30天振蕩的調制，所有高原低渦的活躍期都位于10-30天振蕩的正位相。該結果顯現出10-30天振蕩通過提供有利于（不利于）氣旋式（反氣旋式）環境流場直接調制著高原低渦的活動；大氣低頻振蕩分析表明：10-3

22、0天尺度上，在來自印度季風區低層暖對流引起的對流不穩定配合下，西風槽擾動可激發高原低渦活動。來自高原西南邊界的水汽輸送是對流能量匯聚的一個重要影響因子。本研究結果使我們認識到10-30天季節內振蕩的預測將有助于提升高原低渦及其影響高原下游地區天氣、氣候的中期預報能力。已發表4篇SCI文章：Pengfei Zhang, Guoping Li, Xiouhua Fu, Yimin Liu, Laifang Li. Clustering of Tibetan Plateau vortices by 10-30-day intraseasonal oscillation,Monthly Weather

23、 Review, 2014,142(1):290-300(SCI收錄號：282UX）Chen Gong , Li Guoping* . Dynamic and numerical study of waves in the Tibetan Plateau vortex, Advances in Atmospheric Sciences, 2014, 31(1):131-138（SCI收錄號：277NY）Jiaona Chen, Guoping Li *. Diurnal variation of ground-based GPS-PWV under different solar radiat

24、ion intensity in Chengdu Plain, Journal of Geodynamics, 2013, 72(SI）:81-85. (SCI收錄號：286PZ）Guoping Li, Jia Deng. Atmospheric water monitoring by using ground-based GPS during heavy rains produced by TPV and SWV, Advances in Meteorology, 2013, 1-12(SCI收錄號：276QU） 2013.-2014.4 項目第一署名研究成果根據課題組分工主攻持續性天氣異常

25、的2個研究方向：（1）高原與行星波 （2）TPV and SWV已發表核心期刊文章5篇，一般期刊文章2篇何鈺，李國平*. 青藏高原大地形對華南持續性暴雨影響的數值試驗，大氣科學，2013，37(4): 933-944李國平，趙福虎，黃楚惠，牛金龍. 基于NCEP資料的近30年夏季青藏高原低渦的氣候特征. 大氣科學,2014, 38(4)胡祖恒，李國平*，官昌貴，王紅麗. 中尺度對流系統影響西南低渦持續性暴雨的診斷分析，高原氣象，2014，33（1）：116-129蔣璐君， 李國平*，母靈，孔亮. 基于TRMM資料的西南渦強降水結構分析，高原氣象，2014，33（3）倪成誠,李國平*,熊效振. AIRS資料在中國川藏地區適用性的驗證研究，2013，31（6）：656-663山地學報李國平.高原渦、西南渦研究的新進展及有關科學問題，沙漠與綠洲氣象,2013，7（3）：1-6母靈，李國平.復雜地形對西南低渦生成和移動影響的數值試驗分析，成都信息工程學院學報，2013，28（6）：241-248 目前的研究（SCI錄用1篇，核心期刊錄用2篇，SCI修改2篇，SCI待投稿2篇）蔣璐君，李國平，王興濤.基于TRMM資料的高原渦與西南渦引發強降水的對比研究，大氣科學（錄用）