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气象:2009,35(9):18-28
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北京雷暴大风气候特征及短时临近预报方法
(北京市气象台, 北京 100089)
Climatology and Nowcasting Methods for Thunderstorm Gale in Beijing
(Beijing Weather Forecasting Office, Beijing 100089)
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投稿时间:2009-01-09    修订日期:2009-04-27
中文摘要: 北京地区雷暴大风的预报准确率低而且时效短。为了提高对这种灾害性天气的预警能力,在 气候统计的基础上,研究了潜势预报方法和临近预报算法。对1998—2007年134个雷暴大风 过程 的统计结果表明,北京地区绝大多数的雷暴大风具有下击暴流特征,而且冰雹的落区附近也 是大风的爆发区之一。因此,负浮力的作用和对冰雹具有指示性意义的因子是研究雷暴大风 预报方法应主要考虑的因素。500hPa环流背景分析表明,尽管绝大多数雷暴大风爆发时对流 层中层有干空气侵入,但是还有少数个例产生在偏南暖湿气流中。目前,对后一类大风产生 的机制仍然不清楚。研究表明,当对流层中层有干空气侵入时,有利于雷暴大风出现的环境 条件是:下沉气流具有较大的不稳定性,同时对流层低层环境大气的温度直减率较大。此外 ,还讨论了经验指数——大风指数在北京地区的应用。基于上述的研究,形成了北京地区雷 暴大风短时潜势预报方法,还使用相关分析和多元回归分析技术建立了基于雷达观测和环境 条件的雷暴大风临近预报方程。个例分析表明,临近预报方程对于飑线和弓形回波等带来的 地面大风具有一定的预报能力。
Abstract:Right now, the warning accuracy of the high wind is lower and the lead ing time is also very limited in Beijing. In order to change the situation, the forecasting methods are developed. Based on the statistics for 134 cases, it is known that most of the high wind events are caused by the downbursts and some of them break out while the hails are falling. Therefore, the negative buoyancy an d the hail storm factors should be taken into consideration in study of this sev ere weather. Even though most of the high winds break out when the air at the middl e level becomes drier, there are still a few of events appearing in the warm and wet flow. The mechanism for the latter one is not clear yet. When there is some dry incursion in the middle level of troposphere, the favorable conditions for the h igh wind are the great instability in ambient for downdraft and higher temperatu re lapse rate in the lower level. Besides, the use of WINDEX is also discussed. The potential forecasting method is developed on the basis of above study. Furth ermore, the nowcasting equation on the basis of the radar reflectivity, radial s peed a nd so on as the forecasting factors is given through the correlation analysis an d multiple regression analysis. The case study shows that some strong wind gusts caused by squall line or bow echo could be forecasted successfully by using th e equation. 
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廖晓农,于波,卢丽华,2009.北京雷暴大风气候特征及短时临近预报方法[J].气象,35(9):18-28.
Liao Xiaonong,Yu Bo,Lu Lihua,2009.Climatology and Nowcasting Methods for Thunderstorm Gale in Beijing[J].Meteor Mon,35(9):18-28.