一次高原切变线过程的数值模拟与阶段性结构特征
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摘要
利用非静力中尺度数值模式WRF并结合NCEP-FNL分析资料、常规气象观测资料、FY-2F卫星TBB数据以及CM ORPH降水资料,对2014年6月29日至7月1日的一次高原横切变线过程进行了数值模拟并分析了其演变过程中降水、热力、水汽和动力的结构特征。结果表明,WRF模式较成功地模拟了此次高原切变线过程的降水量和落区。在高原切变线活动期间,不同阶段结构特征存在明显差异。切变线附近通常对应TBB<-20℃的云区;随着切变线的发展,TBB值降低,在云区内有多个TBB<-60℃的对流活动中心,对应主要降水期;在切变线减弱阶段,TBB值升高,降水趋于结束。高原切变线存在"南暖北冷"的热力结构,在切变线发展维持阶段呈现高层稳定、低层不稳定的垂直分布特征;高原切变线也是水汽的聚集带,水汽通量散度的转变对高原切变线的发展具有一定指示作用。在切变线初生阶段和维持、发展阶段,垂直方向上存在正涡度中心和辐合中心,呈现对流层低层正涡度和高位涡中心相耦合的动力结构;气旋式切变有利于高原切变线上正涡度的维持;散度场上的低层辐合、高层辐散的结构特征有利于切变线上垂直上升运动的发展;高原切变线上的辐合带先于正涡度带开始减弱、消失是高原切变线减弱的一种特征信号。
Using the non-hydrostatic mesoscale WRF( Weather Reaserch Forecast) model,and combining with the National Centers for Environment Prediction Final Analysis( NCEP-FNL) data,the conventional observation data,the temperature of black body( TBB) data from the Fengyun-2 F( FY-2 F) satellite and the Climate Prediction Center Morphing Technique( CMORPH) precipitation data,the plateau transverse shear line process occurring from 29 June 2014 to 1 st July was simulated,and the structural characteristics of precipitation,thermodynamic,water vapor and dynamic in the course of evolution were analyzed. The results show that the WRF model successfully simulated the precipition and precipition area caused by the Plateau shear line. During the shear line process,there are significant differences in the structural characteristics of different stages. It usually corresponds to the cloud sector of TBB<-20 ℃ nearby the shear line; with the developing of the shear line,the TBB decreases,and there are many convective activities centers of TBB<-60 ℃,corresponding to the main period of precipitation;TBB increases again during the weakening stage of the shear line and the precipitation goes to end. The plateau shear line has a thermodynamic structure of"warm south but cold north",the vertical distribution characteristic of high level stability and low layer instability appears during the development and maintenance stage of the shear line; the plateau shear line is the water vapor congregated zone,the change of water vapor flux divergence has a certain effect on the development of plateau shear line. Above the vertical direction of the nascent,developing and maintenance stage,there are positive vorticity and converge centers which both present a dynamic system of lower troposphere positive vorticity coupled with the high potential vorticity. The cyclonic shear is favorable for maintaining the positive vorticity of plateau shear line; lower level convergence and upper level divergence structure on divergence field is conducive to the development of vertical ascending motion of the shear line; and it is a characterstic signal of plateau shear line weakened that the converge zone begins to subside then disappear in advance of the positive vorticity does.
Using the non-hydrostatic mesoscale WRF( Weather Reaserch Forecast) model,and combining with the National Centers for Environment Prediction Final Analysis( NCEP-FNL) data,the conventional observation data,the temperature of black body( TBB) data from the Fengyun-2 F( FY-2 F) satellite and the Climate Prediction Center Morphing Technique( CMORPH) precipitation data,the plateau transverse shear line process occurring from 29 June 2014 to 1 st July was simulated,and the structural characteristics of precipitation,thermodynamic,water vapor and dynamic in the course of evolution were analyzed. The results show that the WRF model successfully simulated the precipition and precipition area caused by the Plateau shear line. During the shear line process,there are significant differences in the structural characteristics of different stages. It usually corresponds to the cloud sector of TBB<-20 ℃ nearby the shear line; with the developing of the shear line,the TBB decreases,and there are many convective activities centers of TBB<-60 ℃,corresponding to the main period of precipitation;TBB increases again during the weakening stage of the shear line and the precipitation goes to end. The plateau shear line has a thermodynamic structure of"warm south but cold north",the vertical distribution characteristic of high level stability and low layer instability appears during the development and maintenance stage of the shear line; the plateau shear line is the water vapor congregated zone,the change of water vapor flux divergence has a certain effect on the development of plateau shear line. Above the vertical direction of the nascent,developing and maintenance stage,there are positive vorticity and converge centers which both present a dynamic system of lower troposphere positive vorticity coupled with the high potential vorticity. The cyclonic shear is favorable for maintaining the positive vorticity of plateau shear line; lower level convergence and upper level divergence structure on divergence field is conducive to the development of vertical ascending motion of the shear line; and it is a characterstic signal of plateau shear line weakened that the converge zone begins to subside then disappear in advance of the positive vorticity does.
引文
高文良,郁淑华,2007.高原低涡东移出高原的平均环流场分析[J].高原气象,26(1):206-212.Gao W L,Yu S H,2007.Analyses on mean circulation field of the Plateau Low Vortex moving out of Tibetan Plateau[J].Plateau Meteor,26(1):206-212.
何光碧,师锐,2011.夏季青藏高原不同类型切变线的动力、热力特征分析[J].高原气象,30(3):568-575.He G B,Shi R,2011.Studies on dynamic and thermal characteristics of different Shear Lines over Tibetan Plateau in summer[J].Plateau Meteor,30(3):568-575.
何光碧,师锐,2014.三次高原切变线过程演变特征及其对降水的影响[J].高原气象,33(3):615-625.He G B,Shi R,2014.Analysis on evolution characteristics of three Plateau Shearlines and their effect on precipitation[J].Plateau Meteor,33(3):615-625.DOI:10.7522/j.issn.1000-0534.2013.00023.
黄楚惠,李国平,2007.一次东移高原低涡的天气动力学诊断分析[J].气象科学,27(S1):36-43.Huang C H,Li G P,2007.Synoptic and dynamic diagnostic analysis for a case of Plateau Vortex moving east[J].Sci Meteor Sinica,27(S1):36-43.
李国平,2007.青藏高原动力气象学(第二版)[M].北京:气象出版社,1-271.Li G P,2007.Dynamic meteorology of the Tibetan Plateau,(the second edition)[M].Beijing:China Meteorological Press,1-271.
李山山,李国平,2017.一次鞍型场环流背景下高原东部切变线降水的湿Q矢量诊断分析[J].高原气象,36(2):317-329.Li SS,Li G P,2017.Diagnostic analysis based on Wet Q-Vecter of a Shear line with rain on the east side of Qinghai-Xizang Plateau under the saddle pattern circulation background Field[J].Plateau Meteor,36(2):317-329.DOI:10.7522/j.issn.1000-0534.2016.00025.
李玉兰,1978.高原天气的云图分析[J].气象,4(4):10-12.Li YL,1978.Satellite cloud image analysis of the weather in Tibetan Plateau[J].Meteor Mon,4(4):10-12.
林厚博,游庆龙,焦洋,等,2016.青藏高原及附近水汽输送对其夏季降水影响的分析[J].高原气象,35(2):309-317.Lin H B,You Q L,Jiao Y,et al,2016.Water vapor transportation and its influences on precipitation in summer over Qinghai-Xizang Plateau and its surroudings[J].Plateau Meteor,35(2):309-317.DOI:10.7522/j.issn.1000-0534.2014.00146.
彭新东,程麟生,1992.高原东侧低涡切变线发展的个例数值研究---Ⅰ.分析和诊断[J].兰州大学学报,28(2):163-168.Peng X D,Cheng L S,1992.A case numerical study on the evolution of the Plateau-east-side Low Vortex and Shear-line[J].Journal of Lanzhou University,28(2):163-168.
彭新东,程麟生,1994.高原东侧低涡切变线发展的个例数值研究---Ⅱ.中尺度数值模拟[J].兰州大学学报,30(1):124-131.Peng X D,Cheng L S,1994.A case numerical study on the evolution of the Low Vortex and Shear-line on the east side of the PlateauⅡ.Mesoscale numerical simulation[J].Journal of Lanzhou University,30(1):124-131.
乔全明,谭海清,1984.夏季青藏高原500毫巴切变线的结构与大尺度环流[J].高原气象,3(3):50-57.Qiao Q M,Tan H Q,1984.The structure of 500mb Shear Line and large scale circulation over Qingzang Plateau in summer[J].Plateau Meteor,3(3):50-57.
青藏高原气象科学研究拉萨会战组,1981.夏半年青藏高原500毫巴低涡切变线的研究[M].北京:科学出版社,1-114.Lhasa Group of Tibetan Plateau Meteorology Reserch,1981 Research of500mb Vortex and Shear Lines over the Tibetan Plateau in summer[M].Beijing:Science Press,1-114.
师锐,何光碧,2011.移出与未移出高原的高原切变线大尺度条件分析[J].高原气象,30(6):1453-1461.Shi R,He G B,2011.Contrast analysis on background circulation of Plateau Shear Line moving out and not moving out of the Tibetan Plateau[J].Plateau Meteor,30(6):1453-1461.
寿绍文,2010.位涡理论及其应用[J].气象,36(3):9-18.Shou SW,2010.Theory and application of potential vorticity[J].Meteor Mon,36(3):9-18.
王晖,隆霄,温晓培,等,2017.2012年宁夏“7·29”大暴雨过程的数值模拟研究[J].高原气象,36(1):268-281.Wang H,Long X,Wen X P,et al,2017.Numerical simulation studies on"2012·7·29"rainstorm process in Ningxia[J].Plateau Meteor,36(1):268-281.DOI:10.7522/j.issn.1000-0534.2016.00017.
徐国昌,1983.青藏高原东侧700毫巴切变线的天气气候特征[J].高原气象,2(3):21-25.Xu G C,1983.The climatologically synoptic characteristics of the Shear Line on the 700mb surface to the east of the Qinghai-Xizang Plateau[J].Plateau Meteor,2(3):21-25.
徐国昌,1984.500毫巴高原切变线的天气气候特征[J].高原气象,3(1):36-41.Xu G C,1984.The climatologically synoptic characteristics of the Shear Line on the 500mb surface over the QinghaiXizang Plateau[J].Plateau Meteor,3(1):36-41.
徐建芬,陶健红,夏建平,2000.青藏高原切变线暴雪中尺度分析及其涡源研究[J].高原气象,19(2):187-197.Xu J F,Tao J H,Xia J P,2000.A meso-scale analysis of Qinghai-Xizang Plateau snow storm and its vortex source study[J].Plateau Meteor,19(2):187-197.
杨克明,毕宝贵,李月安,等,2001.1998年长江上游致洪暴雨的分析研究[J].气象,27(8):9-14.Yang K M,Bi B G,Li Y A,et al,2001.On flood-causing torrential rainfall in the upstream district of changjiang river in 1998[J].Meteor Mon,27(8):9-14.
叶笃正,高由禧,陈乾,1977.青藏高原及其紧邻地区夏季环流的若干特征[J].大气科学,(4):289-299.Ye D Z,Gao Y X,Chen Q,1977.Some characteristics of summer circulation in the Tibetan Plateau and its adjacent areas[J].Chinese J Atmos Sci,(4):289-299.
郁淑华,高文良,顾清源,2007.近年来影响我国东部洪涝的高原东移涡环流场特征分析[J].高原气象,26(3):466-475.Yu SH,Gao W L,Gu Q Y,2007.The middle-upper circulation analyses of the Plateau Vortex moving out of Plateau and influencing flood in east China in recent years[J].Plateau Meteor,26(3):466-475.
郁淑华,何光碧,滕家膜,1997.青藏高原切变线对四川盆地西部突发性暴雨影响的数值试验[J].高原气象,16(3):306-311.Yu S H,He G B,Teng J M,1997.The numerical experiments of influence of Shear Line over Qinhai-Xizang Plateau on a sharp heavy rain in west Sichuan basin[J].Plateau Meteor,16(3):306-311.
郁淑华,骆红,1993.青藏高原上低槽与切变线动能收支的个例分析[J].高原气象,12(3):251-256.Yu S H,Luo H,1993.The contrast analysis of kinetic knergy budget for developing trough and Shear Line over the Qinghai-Xizang Plateau[J].Plateau Meteor,12(3):251-256.
张雅斌,马晓华,冉令坤,等,2016.关中地区两次初夏区域性暴雨过程特征分析[J].高原气象,35(3):708-725.Zhang Y B,Ma X H,Ran L K,et al,2016.Characteristic analysis on two regional rainstorms at Guanzhong in Early Summer[J].Plateau Meteor,35(3):708-725.DOI:10.7522/j.issn.1000-0534.2015.00014.
何光碧,师锐,2011.夏季青藏高原不同类型切变线的动力、热力特征分析[J].高原气象,30(3):568-575.He G B,Shi R,2011.Studies on dynamic and thermal characteristics of different Shear Lines over Tibetan Plateau in summer[J].Plateau Meteor,30(3):568-575.
何光碧,师锐,2014.三次高原切变线过程演变特征及其对降水的影响[J].高原气象,33(3):615-625.He G B,Shi R,2014.Analysis on evolution characteristics of three Plateau Shearlines and their effect on precipitation[J].Plateau Meteor,33(3):615-625.DOI:10.7522/j.issn.1000-0534.2013.00023.
黄楚惠,李国平,2007.一次东移高原低涡的天气动力学诊断分析[J].气象科学,27(S1):36-43.Huang C H,Li G P,2007.Synoptic and dynamic diagnostic analysis for a case of Plateau Vortex moving east[J].Sci Meteor Sinica,27(S1):36-43.
李国平,2007.青藏高原动力气象学(第二版)[M].北京:气象出版社,1-271.Li G P,2007.Dynamic meteorology of the Tibetan Plateau,(the second edition)[M].Beijing:China Meteorological Press,1-271.
李山山,李国平,2017.一次鞍型场环流背景下高原东部切变线降水的湿Q矢量诊断分析[J].高原气象,36(2):317-329.Li SS,Li G P,2017.Diagnostic analysis based on Wet Q-Vecter of a Shear line with rain on the east side of Qinghai-Xizang Plateau under the saddle pattern circulation background Field[J].Plateau Meteor,36(2):317-329.DOI:10.7522/j.issn.1000-0534.2016.00025.
李玉兰,1978.高原天气的云图分析[J].气象,4(4):10-12.Li YL,1978.Satellite cloud image analysis of the weather in Tibetan Plateau[J].Meteor Mon,4(4):10-12.
林厚博,游庆龙,焦洋,等,2016.青藏高原及附近水汽输送对其夏季降水影响的分析[J].高原气象,35(2):309-317.Lin H B,You Q L,Jiao Y,et al,2016.Water vapor transportation and its influences on precipitation in summer over Qinghai-Xizang Plateau and its surroudings[J].Plateau Meteor,35(2):309-317.DOI:10.7522/j.issn.1000-0534.2014.00146.
彭新东,程麟生,1992.高原东侧低涡切变线发展的个例数值研究---Ⅰ.分析和诊断[J].兰州大学学报,28(2):163-168.Peng X D,Cheng L S,1992.A case numerical study on the evolution of the Plateau-east-side Low Vortex and Shear-line[J].Journal of Lanzhou University,28(2):163-168.
彭新东,程麟生,1994.高原东侧低涡切变线发展的个例数值研究---Ⅱ.中尺度数值模拟[J].兰州大学学报,30(1):124-131.Peng X D,Cheng L S,1994.A case numerical study on the evolution of the Low Vortex and Shear-line on the east side of the PlateauⅡ.Mesoscale numerical simulation[J].Journal of Lanzhou University,30(1):124-131.
乔全明,谭海清,1984.夏季青藏高原500毫巴切变线的结构与大尺度环流[J].高原气象,3(3):50-57.Qiao Q M,Tan H Q,1984.The structure of 500mb Shear Line and large scale circulation over Qingzang Plateau in summer[J].Plateau Meteor,3(3):50-57.
青藏高原气象科学研究拉萨会战组,1981.夏半年青藏高原500毫巴低涡切变线的研究[M].北京:科学出版社,1-114.Lhasa Group of Tibetan Plateau Meteorology Reserch,1981 Research of500mb Vortex and Shear Lines over the Tibetan Plateau in summer[M].Beijing:Science Press,1-114.
师锐,何光碧,2011.移出与未移出高原的高原切变线大尺度条件分析[J].高原气象,30(6):1453-1461.Shi R,He G B,2011.Contrast analysis on background circulation of Plateau Shear Line moving out and not moving out of the Tibetan Plateau[J].Plateau Meteor,30(6):1453-1461.
寿绍文,2010.位涡理论及其应用[J].气象,36(3):9-18.Shou SW,2010.Theory and application of potential vorticity[J].Meteor Mon,36(3):9-18.
王晖,隆霄,温晓培,等,2017.2012年宁夏“7·29”大暴雨过程的数值模拟研究[J].高原气象,36(1):268-281.Wang H,Long X,Wen X P,et al,2017.Numerical simulation studies on"2012·7·29"rainstorm process in Ningxia[J].Plateau Meteor,36(1):268-281.DOI:10.7522/j.issn.1000-0534.2016.00017.
徐国昌,1983.青藏高原东侧700毫巴切变线的天气气候特征[J].高原气象,2(3):21-25.Xu G C,1983.The climatologically synoptic characteristics of the Shear Line on the 700mb surface to the east of the Qinghai-Xizang Plateau[J].Plateau Meteor,2(3):21-25.
徐国昌,1984.500毫巴高原切变线的天气气候特征[J].高原气象,3(1):36-41.Xu G C,1984.The climatologically synoptic characteristics of the Shear Line on the 500mb surface over the QinghaiXizang Plateau[J].Plateau Meteor,3(1):36-41.
徐建芬,陶健红,夏建平,2000.青藏高原切变线暴雪中尺度分析及其涡源研究[J].高原气象,19(2):187-197.Xu J F,Tao J H,Xia J P,2000.A meso-scale analysis of Qinghai-Xizang Plateau snow storm and its vortex source study[J].Plateau Meteor,19(2):187-197.
杨克明,毕宝贵,李月安,等,2001.1998年长江上游致洪暴雨的分析研究[J].气象,27(8):9-14.Yang K M,Bi B G,Li Y A,et al,2001.On flood-causing torrential rainfall in the upstream district of changjiang river in 1998[J].Meteor Mon,27(8):9-14.
叶笃正,高由禧,陈乾,1977.青藏高原及其紧邻地区夏季环流的若干特征[J].大气科学,(4):289-299.Ye D Z,Gao Y X,Chen Q,1977.Some characteristics of summer circulation in the Tibetan Plateau and its adjacent areas[J].Chinese J Atmos Sci,(4):289-299.
郁淑华,高文良,顾清源,2007.近年来影响我国东部洪涝的高原东移涡环流场特征分析[J].高原气象,26(3):466-475.Yu SH,Gao W L,Gu Q Y,2007.The middle-upper circulation analyses of the Plateau Vortex moving out of Plateau and influencing flood in east China in recent years[J].Plateau Meteor,26(3):466-475.
郁淑华,何光碧,滕家膜,1997.青藏高原切变线对四川盆地西部突发性暴雨影响的数值试验[J].高原气象,16(3):306-311.Yu S H,He G B,Teng J M,1997.The numerical experiments of influence of Shear Line over Qinhai-Xizang Plateau on a sharp heavy rain in west Sichuan basin[J].Plateau Meteor,16(3):306-311.
郁淑华,骆红,1993.青藏高原上低槽与切变线动能收支的个例分析[J].高原气象,12(3):251-256.Yu S H,Luo H,1993.The contrast analysis of kinetic knergy budget for developing trough and Shear Line over the Qinghai-Xizang Plateau[J].Plateau Meteor,12(3):251-256.
张雅斌,马晓华,冉令坤,等,2016.关中地区两次初夏区域性暴雨过程特征分析[J].高原气象,35(3):708-725.Zhang Y B,Ma X H,Ran L K,et al,2016.Characteristic analysis on two regional rainstorms at Guanzhong in Early Summer[J].Plateau Meteor,35(3):708-725.DOI:10.7522/j.issn.1000-0534.2015.00014.