东北地区暴雨、强对流天气的数值模拟诊断研究
|
摘要
应用MM5模式对受华北气旋影响所产生的2003年8月5～6日东北地区暴雨天
气进行了数值模拟，较成功地模拟出了这次过程。大范围偏南气流及其中的中尺度
急流带来的水汽输送及辐合，为暴雨天气的发生、发展提供了低层水汽条件。中层
干冷空气下沉及低层暖湿气流爬升是强对流不稳定能量积累的重要机制。能量锋区
为产生强对流提供了能量条件。低层低空急流脉动产生的强辐合，高空急流诱发的
高层强辐散是本次东北地区暴雨天气的直接触发机制。对流层中低层比较大的垂直
速度为强对流的触发提供了动力条件。
通过对等熵面的位涡分析，发现了对流层中低层的位涡场，在气旋上方有一个
相对高位涡中心，由此使得气旋在一个比较深厚的气旋性环流中发展；而对流层高
层则是一个伴有较强位涡低值的反气旋环流区。低层的气旋性环流和高层的反气旋
性环流相配合，有利于形成低层辐合，高层辐散，使得气旋附近的上升气流得以维
持和加强，从而为对流性降水提供了必要条件。通过对等压面的位涡分析，发现了在
暴雨发生前，在对流层低层有正位涡扰动存在并向北形成倾斜的扰动柱，同时也反
映了对流层低层正位涡扰动对强对流天气的触发作用；随后高层正位涡向下扰动，
形成一个垂直扰动柱，这时对应降水的发展阶段：在暴雨的鼎盛阶段，600～700hpa
上空维持水平分布的等值线，在其上还有正的位涡扰动；当近地面出现负的位涡扰
动时，降水随之也减弱。
分析表明Q矢量散度场多呈条块状的辐合、辐散区相间分布的形式，反映了中
尺度特性。在对流层低层Q矢量散度辐合区和辐散区的交界处，伴随有较大的对流
性降水，对流性降水的强度随辐合中心强度的增强而增强，随辐合中心强度的减弱
而减弱。
通过分析我们发现了正的相对螺旋度中心与850hpa低空急流的演变过程是一
致的。在正的相对螺旋度中心的左侧，3小时后出现3h积云降水量的高值中心，也
就是说正的相对螺旋度中心和3h积云降水中心不同步，3h积云降水中心落后于相
对螺旋度中心。相对螺旋度值的变化大致反映了暴雨及其系统的强弱趋势。
A rainstorm in northeast China affected by the North China cyclone during 5~ 6 August 2003, was successfully simulated by MM5 model in dais paper. Big scope south airflow and vapor transport and convergence brought by meso-scale jet, offer vapor condition which rainstorm occur and develop. Energy front has offered energy condition to produce severe convection. Severe convergence brought by Low-level jet pulsation, and severe divergence brought by upper-level jet is directly trigger mechanism of this intense rainstorm. The severe vertical velocity is severe convection trigger to offer dynamical condition for severe convection generation in lower-troposphere.
Through analysis of potential vorticity in equity-entropy surface field, a relatively high potential vorticity center in cyclone top in low-troposphere have discovered, and make cyclone develop in a more deep cyclone circulation by this; And an anticyclone circulation zone with more severe low potential vorticity in high-troposphere. Low-level cyclone circulation with high-level anticyclone circulation, is helpful to form low-level convergence and high-level divergence, and make the rising airflow nearby cyclone keep and strengthen so that have offered necessity condition for convection precipitation. Through analysis of potential vorticity in isobaric surface field, in low-troposphere a positive potential vorticity disturbance exist and form incline disturbance column northward before rainstorm generation, at the same time have also reflected positive potential vorticity disturbance for severe convection weather trigger role in lower-troposphere; Soon positive potential vorticity disturbance in high-troposphere downward, form one vertical disturbance column, now corresponding precipitation develop stage; In the prosperous stage of rainstorm that maintains isolines of horizontal distribution and still have straight positive potential vorticity disturbance in 600 -700 hpa isobaric surface field; When near ground arises negative potential vorticity disturbance, precipitation also weaken.
Q vector divergence field submit piece form district of convergence and divergence,
have reflected meso-scale character. In the interface of convergence district and divergence district of Q vector divergence, accompany severe convection precipitation and convection precipitation strengthen following convergence center strength, weaken following divergence center weaken.
The positive storm-relative helicity center is accompany with low-level jet in 850-hpa isobaric surface fields. Severe cumulus precipitation of 3h center appear in the left side of positive stonn-relative helicity center, i.e. positive storm-relative helicity center is not synchronization with cumulus precipitation center of 3h, the cumulus precipitation center of 3h falls behind the positive storm-relative helicity center. The change of the positive stonn-relative helicity value has reflected the severe weak tendency of rainstorm and its system approximately.
气进行了数值模拟，较成功地模拟出了这次过程。大范围偏南气流及其中的中尺度
急流带来的水汽输送及辐合，为暴雨天气的发生、发展提供了低层水汽条件。中层
干冷空气下沉及低层暖湿气流爬升是强对流不稳定能量积累的重要机制。能量锋区
为产生强对流提供了能量条件。低层低空急流脉动产生的强辐合，高空急流诱发的
高层强辐散是本次东北地区暴雨天气的直接触发机制。对流层中低层比较大的垂直
速度为强对流的触发提供了动力条件。
通过对等熵面的位涡分析，发现了对流层中低层的位涡场，在气旋上方有一个
相对高位涡中心，由此使得气旋在一个比较深厚的气旋性环流中发展；而对流层高
层则是一个伴有较强位涡低值的反气旋环流区。低层的气旋性环流和高层的反气旋
性环流相配合，有利于形成低层辐合，高层辐散，使得气旋附近的上升气流得以维
持和加强，从而为对流性降水提供了必要条件。通过对等压面的位涡分析，发现了在
暴雨发生前，在对流层低层有正位涡扰动存在并向北形成倾斜的扰动柱，同时也反
映了对流层低层正位涡扰动对强对流天气的触发作用；随后高层正位涡向下扰动，
形成一个垂直扰动柱，这时对应降水的发展阶段：在暴雨的鼎盛阶段，600～700hpa
上空维持水平分布的等值线，在其上还有正的位涡扰动；当近地面出现负的位涡扰
动时，降水随之也减弱。
分析表明Q矢量散度场多呈条块状的辐合、辐散区相间分布的形式，反映了中
尺度特性。在对流层低层Q矢量散度辐合区和辐散区的交界处，伴随有较大的对流
性降水，对流性降水的强度随辐合中心强度的增强而增强，随辐合中心强度的减弱
而减弱。
通过分析我们发现了正的相对螺旋度中心与850hpa低空急流的演变过程是一
致的。在正的相对螺旋度中心的左侧，3小时后出现3h积云降水量的高值中心，也
就是说正的相对螺旋度中心和3h积云降水中心不同步，3h积云降水中心落后于相
对螺旋度中心。相对螺旋度值的变化大致反映了暴雨及其系统的强弱趋势。
A rainstorm in northeast China affected by the North China cyclone during 5~ 6 August 2003, was successfully simulated by MM5 model in dais paper. Big scope south airflow and vapor transport and convergence brought by meso-scale jet, offer vapor condition which rainstorm occur and develop. Energy front has offered energy condition to produce severe convection. Severe convergence brought by Low-level jet pulsation, and severe divergence brought by upper-level jet is directly trigger mechanism of this intense rainstorm. The severe vertical velocity is severe convection trigger to offer dynamical condition for severe convection generation in lower-troposphere.
Through analysis of potential vorticity in equity-entropy surface field, a relatively high potential vorticity center in cyclone top in low-troposphere have discovered, and make cyclone develop in a more deep cyclone circulation by this; And an anticyclone circulation zone with more severe low potential vorticity in high-troposphere. Low-level cyclone circulation with high-level anticyclone circulation, is helpful to form low-level convergence and high-level divergence, and make the rising airflow nearby cyclone keep and strengthen so that have offered necessity condition for convection precipitation. Through analysis of potential vorticity in isobaric surface field, in low-troposphere a positive potential vorticity disturbance exist and form incline disturbance column northward before rainstorm generation, at the same time have also reflected positive potential vorticity disturbance for severe convection weather trigger role in lower-troposphere; Soon positive potential vorticity disturbance in high-troposphere downward, form one vertical disturbance column, now corresponding precipitation develop stage; In the prosperous stage of rainstorm that maintains isolines of horizontal distribution and still have straight positive potential vorticity disturbance in 600 -700 hpa isobaric surface field; When near ground arises negative potential vorticity disturbance, precipitation also weaken.
Q vector divergence field submit piece form district of convergence and divergence,
have reflected meso-scale character. In the interface of convergence district and divergence district of Q vector divergence, accompany severe convection precipitation and convection precipitation strengthen following convergence center strength, weaken following divergence center weaken.
The positive storm-relative helicity center is accompany with low-level jet in 850-hpa isobaric surface fields. Severe cumulus precipitation of 3h center appear in the left side of positive stonn-relative helicity center, i.e. positive storm-relative helicity center is not synchronization with cumulus precipitation center of 3h, the cumulus precipitation center of 3h falls behind the positive storm-relative helicity center. The change of the positive stonn-relative helicity value has reflected the severe weak tendency of rainstorm and its system approximately.
引文
1 周琳等．东北气候．气象出版社，1991．
2 寿绍文．中尺度天气动力学．气象出版社，北京，1993．
3 Doswell , C.A. The distinction between large-scale and mesoscale contribution to severe convection: A case study example. Wea. and Forecasting. 1987,3～16.
4 Shou-Jun Chen, Ying-Hwa Kuo etc. A Modeling Case Study of Heavy Rainstorms alone the Mei-Yu Front. Monthly weather review. 1998,126(9),2330～2351.
5 彭治班，刘健文等．国外强对流天气的应用研究．气象出版社，2001，51～370．
6 朱乾根，林锦瑞，寿绍文．天气学原理和方法．气象出版社，1992
7 陶诗言．中国之暴雨．北京，科学出版社，1980
8 Marwitz J. D. The structure and motion of severe hailstorms, partⅠ:Supercell storms. J. Appl. meteor. 1972,11,166～179.
9 Brooks, H.E. Dowell, C.A. The role of midtroposphric winds in the evolution and maintenance of low-level mesocyclones. Mon. Wea. Rev. 1994,122,126～136.
10 Fovell, R.G. Numerical simulation of a midlatitude squll line in two dimention. J. Atmas. Sci. 1988,45,3846～3879.
11 Romero R. Observations and fine grid simulation of a convective outbreak in northeastern Spain: Importance of diurnal forcing and convective cold pools. Monthly weather review. 2001,129(9),2157～2182.
12 W．R．Cotton，R．A．Anthes．风暴和云动力学．气象出版社，1993，782．
13 斯公望．暴雨和强对流环境系统．气象出版社，1989，116．
14 孙力，安刚．1998年松嫩流域东北冷涡大暴雨过程诊断分析．大气科学，2001，25(3)，342～343．
15 周毅，刘宇迪等．现代数值天气预报．气象出版社．2002，124～126．
16 刘式适，刘式达．大气动力学，北京大学出版社，1999，50～57．
17 李耀辉，寿绍文，旋风螺旋度及其在暴雨演变过程中的作用．南京气象学院学，1999，Vol．22，No．1，95～102．
18 袁佳双，寿绍文，高低空位涡扰动、非绝热加热与气旋的发生发展．热带气象学报，2002，Vol．18，No．2，121～130．
19 吴正华．京津冀地区短历时降水和冰雹的气候研究．中尺度气象文集，1993，168．
20 陆汉城．中尺度天气原理和预报，气象出版社，2000，59～71．
21 孔燕燕，沈建国．强雷暴预报，气象出版社，2001，16～23．
22 王建捷等．北京地区中尺度非静力模式预报系统的开发与实时预报应用．应用
气象学报，1999，10(4)，385～389．
23 寿绍文、王祖锋，1991年7月上旬贵州地区暴雨过程物理机制的诊断研究．气象科学，1998，Vol．18，No．3，231～238．
24 吴海英、寿绍文，位涡扰动与气旋发展．南京气象学院学报2002，Vol．25，No．4，510～517．
25 杨红梅，赵亚民等．冷涡暴雨的物理结构及概念模型．中尺度气象文集，1993，231．
26 孙力，廉毅，东北地区一次突发性暴雨分析，高原气象，1995，Vol．14，No．4．
27 孙力，安刚，高枞亭等，1998年夏季嫩江和松花江流域东北冷涡暴雨的成因分析，应用气象学报，2002，Vol．13，No．2．
28 郑秀雅，张廷治，白人海．东北暴雨．北京：气象出版社，1992．
29 孙力，安刚，1998年夏季嫩江和松花江流域东北冷涡暴雨的成因分析，大气科学，2001，Vol．25，No．3．
30 孙力，廉毅，白乐生，东北地区一次突发性暴雨分析，1995，高原气象Vol．14，No．4．
31 Davies J R, Donald Burgest. test of helicity as a tornado forcast parameter. In:Amer Met Soc ed. 16th of conf on severe local storm. Alta(Canada):1990.588～592.
32 Rossby C G. relation between variations in the intensity of the zonal circulation of the atmosphere and the displacements of the semi-permanentcenters of action[J].J marine rev, 1939,2(1):38～55.
33 Rossby C G. Planetary flow patterns in the atmosphere[J].Q J R Meteorol Soc, 1940,66(suppl):68～87.
34 Ertel H. Binneuer hydrodynamischer Wirbelsatz[J].Met Z, 1942,59:277～281.
35 田珍富，滕俏彬，王作述．一次局地特大暴雨湿位涡的中尺度分析[J]．热带气象学报，1998，14(2)：163～172．
36 盛华，“81·7”大暴雨位涡与相当位涡的诊断分析，高原气象，1984，3(3)：10～18．
37 吴国雄、蔡雅萍、唐晓菁，湿位涡和倾斜位涡发展，气象学报，1995，53(4)：378～405．
38 Hoskins B J. The role of potential vorticity in symmetric stability and instability[J].Q J R Meteorol Soc, 1974,100:480～482.
2 寿绍文．中尺度天气动力学．气象出版社，北京，1993．
3 Doswell , C.A. The distinction between large-scale and mesoscale contribution to severe convection: A case study example. Wea. and Forecasting. 1987,3～16.
4 Shou-Jun Chen, Ying-Hwa Kuo etc. A Modeling Case Study of Heavy Rainstorms alone the Mei-Yu Front. Monthly weather review. 1998,126(9),2330～2351.
5 彭治班，刘健文等．国外强对流天气的应用研究．气象出版社，2001，51～370．
6 朱乾根，林锦瑞，寿绍文．天气学原理和方法．气象出版社，1992
7 陶诗言．中国之暴雨．北京，科学出版社，1980
8 Marwitz J. D. The structure and motion of severe hailstorms, partⅠ:Supercell storms. J. Appl. meteor. 1972,11,166～179.
9 Brooks, H.E. Dowell, C.A. The role of midtroposphric winds in the evolution and maintenance of low-level mesocyclones. Mon. Wea. Rev. 1994,122,126～136.
10 Fovell, R.G. Numerical simulation of a midlatitude squll line in two dimention. J. Atmas. Sci. 1988,45,3846～3879.
11 Romero R. Observations and fine grid simulation of a convective outbreak in northeastern Spain: Importance of diurnal forcing and convective cold pools. Monthly weather review. 2001,129(9),2157～2182.
12 W．R．Cotton，R．A．Anthes．风暴和云动力学．气象出版社，1993，782．
13 斯公望．暴雨和强对流环境系统．气象出版社，1989，116．
14 孙力，安刚．1998年松嫩流域东北冷涡大暴雨过程诊断分析．大气科学，2001，25(3)，342～343．
15 周毅，刘宇迪等．现代数值天气预报．气象出版社．2002，124～126．
16 刘式适，刘式达．大气动力学，北京大学出版社，1999，50～57．
17 李耀辉，寿绍文，旋风螺旋度及其在暴雨演变过程中的作用．南京气象学院学，1999，Vol．22，No．1，95～102．
18 袁佳双，寿绍文，高低空位涡扰动、非绝热加热与气旋的发生发展．热带气象学报，2002，Vol．18，No．2，121～130．
19 吴正华．京津冀地区短历时降水和冰雹的气候研究．中尺度气象文集，1993，168．
20 陆汉城．中尺度天气原理和预报，气象出版社，2000，59～71．
21 孔燕燕，沈建国．强雷暴预报，气象出版社，2001，16～23．
22 王建捷等．北京地区中尺度非静力模式预报系统的开发与实时预报应用．应用
气象学报，1999，10(4)，385～389．
23 寿绍文、王祖锋，1991年7月上旬贵州地区暴雨过程物理机制的诊断研究．气象科学，1998，Vol．18，No．3，231～238．
24 吴海英、寿绍文，位涡扰动与气旋发展．南京气象学院学报2002，Vol．25，No．4，510～517．
25 杨红梅，赵亚民等．冷涡暴雨的物理结构及概念模型．中尺度气象文集，1993，231．
26 孙力，廉毅，东北地区一次突发性暴雨分析，高原气象，1995，Vol．14，No．4．
27 孙力，安刚，高枞亭等，1998年夏季嫩江和松花江流域东北冷涡暴雨的成因分析，应用气象学报，2002，Vol．13，No．2．
28 郑秀雅，张廷治，白人海．东北暴雨．北京：气象出版社，1992．
29 孙力，安刚，1998年夏季嫩江和松花江流域东北冷涡暴雨的成因分析，大气科学，2001，Vol．25，No．3．
30 孙力，廉毅，白乐生，东北地区一次突发性暴雨分析，1995，高原气象Vol．14，No．4．
31 Davies J R, Donald Burgest. test of helicity as a tornado forcast parameter. In:Amer Met Soc ed. 16th of conf on severe local storm. Alta(Canada):1990.588～592.
32 Rossby C G. relation between variations in the intensity of the zonal circulation of the atmosphere and the displacements of the semi-permanentcenters of action[J].J marine rev, 1939,2(1):38～55.
33 Rossby C G. Planetary flow patterns in the atmosphere[J].Q J R Meteorol Soc, 1940,66(suppl):68～87.
34 Ertel H. Binneuer hydrodynamischer Wirbelsatz[J].Met Z, 1942,59:277～281.
35 田珍富，滕俏彬，王作述．一次局地特大暴雨湿位涡的中尺度分析[J]．热带气象学报，1998，14(2)：163～172．
36 盛华，“81·7”大暴雨位涡与相当位涡的诊断分析，高原气象，1984，3(3)：10～18．
37 吴国雄、蔡雅萍、唐晓菁，湿位涡和倾斜位涡发展，气象学报，1995，53(4)：378～405．
38 Hoskins B J. The role of potential vorticity in symmetric stability and instability[J].Q J R Meteorol Soc, 1974,100:480～482.