设为首页
加入收藏
1998年7月河套气旋强烈发展时的暴雨过程分析
Diagnosis of a Heavy Rain Event Caused by the Intense Development of Yellow River Cyclone in July, 1998
-
摘要: 采用位涡理论对1998年7月4—7日的一次河套气旋强烈发展中的暴雨过程进行分析。结果表明：此次夏季河套气旋的强烈发展是在高层正位涡平流和低层暖平流的共同作用下产生的。高空双急流结构产生的强烈辐散加强了低层辐合，有利于气旋的加强。强降水出现在河套气旋强烈发展过程中，是由高层冷空气与季风涌带来的西南暖湿气流辐合而引起的大尺度降水过程。在这次气旋强烈发展过程中，对流层低层到中上层均出现强的上升气流，使得南方深厚的暖湿空气不断随西南风流入暴雨区上空。暴雨发生时，华北地区处于地面Ω型的θse高能舌之中，其上空500 hPa存在一个由大尺度动力强迫形成的东北—西南向的非地转湿 Q 矢量辐合带，对流云带与 Q 矢量辐合中心有非常好的对应关系。Abstract: A Yellow River cyclone intensifies rapidly during July 5 to 7, 1998. Its center pressure decreases by 12 hPa over a 24 h period and it produces heavy rain with the maximum rainfall exceeding 350 mm in Beijing. A diagnostic study is conducted from a potential vorticity or "PV thinking" perspective using NCAR/NCEP 6 hourly reanalysis data. The results show that the rapid development of the Yellow River Cyclone is related to the coupling between a surface low system and an upper level positive PV anomaly. When the positive PV anomaly near the tropopause advects over a pre existing surface cyclone, the cyclone deepens dramatically. Warm advection at 850 hPa intensifies the development of cyclone. Heavy rain occurs in the rapid intensification stage of the Yellow River Cyclone. This is a synoptic scale precipitation case, which is caused by the convergence between cold air descending from stratosphere and southwest warm and moisture air flow brought by the Monsoon Surge. On the vertical cross section through the region of heavy rain, abrupt jump of tropopause is shown clearly. The tropopause is near 250 hPa on the cold side and rises dramatically to above 100 hPa on the warm side. The extent of the descent of stratospheric air in the storm can be deduced by the tongue of 1 PVU extending from 200 to 600 hPa.While the cyclone intensifies rapidly, there are strong ascending motions, which lead to the deep moisture air from the south of China transporting to the heavy rain region continually by southwest wind. From the low to mid level of trop osphere, the humidity increases. The amount of precipitable water vapor increases 10.2 mm in 24 hours. The atmosphere is baroclinic over heavy rain region. High level jet with wind speed greater than 30 m·s-1 and low level jet with wind speed greater than 12 m·s-1 are found at 200 hPa and 850 hPa, respectively. At surface, a tongue of high θse value prevails in North China. At 500 hPa, there is a convergent zone of non geostrophic wet Q vector extending from southwest to northeast, which is caused by the large scale force. The convective cloud bands have a good relationship with the convergent center of Q vector. In the convergence zone, a number of MCSs continuously move to North China alone the southwest wind on the northwest side of the Subtropical High and cause amount of rainfall. It is called "train effect". Furthermore, topography influences the location of heavy rain. East wind prevails at surface over Beijing area when rainfall occurs. The west mountain blocks and lifts the east flow and increases the precipitation on upstream side of the mountain. The maximum precipitation centers occur at Changping, Yanqing.
-
图 1 1998年6月16日—7月16日华北地区主要降水过程与天气系统配置
(a)沿37.5°~42.5°N平均的500 hPa正相对涡度(单位:10-6s-1)的纬向-时间剖面,(b)(d)(f)华北地区35站平均的逐日降水量R,(c)110°~120°E平均的200 hPa西风分量的时间-经向剖面(长虚线为气候平均的20 m·s-1风速线) (e)110°~120°E整层(地面~300 hPa)水汽通量平均(箭头, 单位:kg·m -1·s-1)和TBB≤0 ℃的区域(阴影区), (g)30°~32°N平均的向外长波辐射距平≤-15 W·m -2的区域(实线)与500 hPa位势高度
Fig. 1 The main rainfalls in Huabei and the corresponding circulation pattern from June 16 to July 16, 1998
(a)zone-time section of 500 hP a positive relative vo rticity averaged within 37.5°—42.5°N,(b)(d)(f)averaging daily precipitation of 35 stations in Huabei,(c)time-meridian section of 200 hPa west wind, averaged within 110°—120°E(dashed lines denote isobaths of west wind with value of 20 m·s -1 in climate),(e)integrated water vapor flux from surface to 300 hPa averaged within 110°—120°E(arrow, unit:kg·m-1·s-1, regions with TBB≤0℃ are shaded),(g)zone-time section of averaged OLRA within 30°—32°N(solid lines)and 500 hPa geopotential height(shaded from light to dark denote 586, 588, 592 dagpm, dashed line denotes 586 dagpm contour in climate)
图 2 1998年θ=350 K等熵面的位涡分布(单位:10-6 km2·kg-1·s-1)
(a)7月5日00:00,(b)7月5日12:00,(c)7月6日00:00,(d)7月7日00:00
Fig. 2 Potential vorticity(unit :10-6 km2·kg-1·s-1)on the 350 Kisentropic surface at(a)00 :00 on July 5, 1998,(b)12 :00 on July 5, 1998,(c)00 :00 on July 6, 1998,(d)00 :00 on July 7, 1998
图 3 1998年7月5日12 :00沿图 2b中A—B线的剖面图
(a)位涡(单位:PVU),(b)等风速线(实线, 单位:m·s-1)及风矢量(垂直速度×100)和位温(虚线, 单位:K)
Fig. 3 Vertical section along A—B line in Fig.2b at 12:00 on July 5
(a)potential vorticity(unit :PVU), (b)wind speed(solid line, unit:m·s-1)with wind vector and potential temperature(dashed line, unit:K)
图 4 1998年7月5日12 :00(a)350 K等熵面位涡(实线, 仅绘出1~4 PVU)和850 hPa暖平流区(阴影区, 单位:10-5K·s-1)(b)GMS红外云顶亮温(阴影区, 单位:℃, 虚线为TBB=-12℃)
Fig. 4 350 K PV(solid line, with contour from 1—4 PVU)and 850 hPa warm advection region(shaded areas, unit :10 -5K·s-1)(a)and TBB retrieved from GMS data(shaded areas, unit :℃; dashed line denotes-12℃)(b)at 12:00 on July 5, 1998
图 5 1998年7月4—7日θ=310 K等熵面天气形势分布
(实线为等压线, 单位:hPa; 虚线为等比湿线, 单位:g·kg-1, 阴影区为比湿大于10 g·kg-1的区域) (a)7月4日00 :00,(b)7月5日12 :00,(c)7月6日00 :00,(d)7月7日00 :00
Fig. 5 Isobars(solid line, unit :hPa)and mix ratio contours(dashed line, unit:g·kg-1)at 310 K isentropic surfaces for July 4—7, 1998(region with mix ratio value greater than 10 g/kg are shaded) (a)00 :00 on July 4,(b)12:00 on July 5,(c)00 :00 on July 6,(d)00:00 on July 7
图 7 1998年7月5日12 :00暴雨区天气系统配置
(a)500 hPa位势高度(>586 dagpm, 实线)、200 hPa风速(>30 m·s-1, 风向杆)、850 hPa水汽通量矢量(>0.15 m·s-1, 箭头)和850 hPa比湿(>12 g·kg-1, 阴影区), (b)地面θse(>335 K, 实线)、500 hPa Q矢量(箭头)及∇·Q(低于-0.5×10-15 m·kg-1·s-1, 阴影区)
Fig. 7 Synoptic pattern of heavy rain region for 12:00 on July 5, 1998
(a)500 hPa height(with values greater than 586 dagpm, solid line), 200 hPa wind(with speed greater than 30 m·s -1, wind bar), 850 hPa water vapor flux(with values greater than 0.15 m·s-1, arrow)and 850 hPa mix ratio(with greater than 12 g·kg-1, shaded), (b)surface θse(with values greater than 335 K, solid line), 500 hPa Q vector(arrows)and Q vector divergence(values less than-0.5×10-15 m·kg-1·s-1, shaded)
-
[1] 陶诗言.中国之暴雨.北京:气象出版社, 1980. [2] 蒋尚城.8.26黄河气旋暴雨分析.科学通报, 1990, 35(19):1481-1483. http://www.cnki.com.cn/Article/CJFDTOTAL-KXTB199019012.htm [3] 李修芳.影响华北地区的黄河气旋过程分析.气象, 1997, 23(1):17-22. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXX701.002.htm [4] 田生春.刘苏红.一次快速发展气旋的诊断分析.气象学报, 1988, 46(3), 285-293. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB198803004.htm [5] 梁丰, 陶诗言, 张小玲.华北地区一次黄河气旋发生发展时所引起的暴雨诊断分析.应用气象学报, 2006, 17(3):257-265. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20060346&flag=1 [6] 丁一汇, 朱彤.陆地爆发性气旋发展的动力学分析和数值模拟.中国科学(B辑), 1993, 23(11):1226-1232. http://www.cnki.com.cn/Article/CJFDTOTAL-JBXK199311015.htm [7] 张杰英, 杨梅玉, 姜达雍.考虑大尺度凝结加热的数值模拟试验.气象科学研究院院刊, 1987, 2(2):123-132. http://www.cnki.com.cn/Article/CJFDTOTAL-YYQX198702001.htm [8] Hoskins B J, McIntyre M E, Ribertson A W.On the use and significance of isentropic potential vorticity maps.Quart J Roy Meteor Soc, 1985, 111:877-946. doi: 10.1002/qj.49711147002 [9] Hoskins B J, Berrisford P.A potential vorticity perspective on the storm of 15-16 October 1987.Weather, 1988, 43:122-129. doi: 10.1002/wea.1988.43.issue-3 [10] Hoskins B J.A potential vorticity view of synoptic development.Meteor Appl, 1997, 4:325-334. doi: 10.1017/S1350482797000716 [11] Bleck R.Depiction of upper/lower vortex interaction associated with extratropical cyclogenesis.Mon Wea Rev, 1990, 118:573-585. doi: 10.1175/1520-0493(1990)118<0573:DOUVIA>2.0.CO;2 [12] 吴国雄, 蔡雅萍, 唐晓菁.湿位涡和倾斜涡度发展.气象学报, 1995, 53(4):378-405. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB504.001.htm [13] 吴国雄, 蔡雅萍.风垂直切变和下滑倾斜涡度发展.大气科学, 1997, 21(3):273-282. http://www.cnki.com.cn/Article/CJFDTOTAL-DQXK703.002.htm [14] Stoelinga M.A potential vorticity-based study of the role of diabatic heating and friction in a numerically simulated cyclone.Mon Wea Rev, 1996, 124:849-874. doi: 10.1175/1520-0493(1996)124<0849:APVBSO>2.0.CO;2 [15] 寿绍文, 李耀辉, 范可.暴雨中尺度气旋发展的等熵面位涡分析.气象学报, 2001, 59(5):560-568. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXB200105006.htm [16] 丁治英, 王劲松, 翟兆锋.爆发性气旋的合成诊断及形成机制研究.应用气象学报, 2001, 12(1):30-40. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20010104&flag=1 [17] 姜学恭, 沈建国, 刘景涛, 等.地形影响蒙古气旋发展的观测和模拟研究.应用气象学报, 2004, 15(5):601-611. http://qikan.camscma.cn/jams/ch/reader/view_abstract.aspx?file_no=20040573&flag=1 [18] 杨克明.每月天气.气象, 1998, 24(10):58-61. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXX905.012.htm [19] 李廷福, 廖晓农, 俞连芬."98·7"北京大暴雨的中尺度分析.气象, 1999, 25(5):44-48. http://www.cnki.com.cn/Article/CJFDTOTAL-QXXX905.009.htm [20] Belville J D, Stewart N O.Extreme Rainfall Events in Louisiana:The "New Orleans Type".Preprints, 5th Conference on Hydrometeorology.Tulsa, Ok, Amer Meteor Soc, 1983:284-290. [21] Corfidi C D, Junker N W, Glass F H.The Louisiana/Mississippi Flash Flood and Severe Weather Outbreak of 15-16 November 1987.Preprints, 16th Conference on Severe Local Storms.Alberta, Canada, Amer Meteor Soc, 1990:627-633. [22] 雷雨顺.能量天气学.北京:气象出版社, 1986. -
下载:
计量
- 摘要浏览量: 3097
- HTML全文浏览量: 743
- PDF下载量: 2076
- 被引次数: 0
