| 变分多普勒雷达分析系统对北京一次强降水过程的短时预报能力初探 |
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| 引用本文： | 耿建军,肖现,王迎春,顾松山,SunJuanzhen.变分多普勒雷达分析系统对北京一次强降水过程的短时预报能力初探[J].南京气象学院学报,2012(6):730-736. |
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| 作者姓名： | 耿建军 肖现 王迎春 顾松山 SunJuanzhen |
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| 作者单位： | [1]北京市气象台,北京100089 [2]中国气象局北京城市气象研究所,北京100086 [3]南京信息工程大学大气物理学院,江苏南京210044 [4]美国国家大气科学研究中心,ColoradoBoulder80307 |
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| 基金项目： | 公益性行业（气象）科研专项（GYHY200706004） |
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| 摘 要： | 利用四维变分多普勒雷达资料分析系统对2008年7月30日北京一次强降水过程反演得到的风场和微物理场进行分析，针对本过程中东段回波减弱消散、强降水区的确定、降水回波的转向几个短时临近预报关键点进行讨论，得出如下初步结论：1）在东段降水回波减弱消散前的12～24min，其对应的4．7km高度扰动温度场正值区出现“u”形中空结构，甚至在中空结构中有负值区出现，同时1．7km高度垂直速度场有上升气流与下沉气流分离的现象；2）如果4．7km高度扰动温度场的相对大值区在某地区持续时间较长（2h左右）或者某区域扰动温度迅速增加且出现大值中心（大于2oC）并维持，那么该区域未来1～2h内出现较强降水的可能性较大；3）降水回波的转向是受到1．7km高度在密云、平谷境内出现的反气旋型环流西部气流的引导，而该环流的出现则是北京西部持续强降水区的辐合上升气流在中高层水平输送到北京东部的密云、平谷境内并在该处形成下沉辐散的反气旋型环流反作用于降水回波所致，环流的形成早于回波转向约1h。
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| 关 键 词： | 变分多普勒雷达分析系统 强降水短时预报 扰动温度 回波转向 |
A preliminary exploration on the nowcasting ability of VDRAS in a rainstorm case in Beijing |
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| Institution: | GENG Jian-jun , XIAO Xian, WANG Ying-chun, GU Song-shan, SUN Juan-zhen ( 1. Meteorological Observatory of Beijing, Beijing 100089, China ;2. Institute of Urban Meteorology, CMA, Beijing 100086, China; 3. School of Atmospheric Physics, NUIST, Nanjing 210044, China ;4. National Center for Atmospheric Research, Colorado 80307, USA) |
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| Abstract: | A fourdimensional variational Doppler radar analysis system （VDRAS） is used to analyze the three dimensional wind fields and microphysical fields of a rainstorm case in Beijing on July 30, 2008. After discussing some key points in shortterm and nowcasting forecast such as the weakening and dissipation of the eastern echo as well as heavy rain area and the turning of echo, some preliminary con clusions were obtained： 1 ） 1224 minutes before the weakening and dissipation of the eastern echo, a hollow structure （even negative point） appeared in corresponding analyzed perturbation temperature positive region at the height of 4. 7 km, and at the same time ascending and descending flow separated in the same region at the height of 1.7 km. 2） If the duration of the analyzed perturbation temperature in some regions was higher than that in other regions for 2 hours or longer, or the perturbation tempera ture increased rapidly in few minutes and reached the extreme value （above 2 ℃ ）, there was a good chance that heavy rain would occur in 12 hours in this region. 3 ） The turning of the echo was con ducted by the western air flow of anticyclone style circulation flow at the height of 1.7 km. A conver gence ascending flow was horizontally transported from western region to Miyun and Pinggu in the eastem region, and then a divergence descending flow of anticyclone type came into being. The moving of radar echo was affected by the air flow and this flow occurred about 1 hour before the echo turning. |
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| Keywords: | VDRAS rainstorm nowcasting perturbation temperature echo turning |
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