1999年欧洲圣诞节风暴数值模拟分析

对1999年圣诞期间发生在欧洲中西部的圣诞节风暴进行了分析，认为4个主要的低气压系统中的第二个给法国北部带来了强风暴雨，巴黎的Orly机场阵风速度〉47m／s；第四个低压系统沿法国西海岸产生相似的恶劣天气，并在西班牙的北部海岸及地中海沿岸国家造成了毁灭性的破坏。在法国中部风暴最剧烈的时候，最大阵风〉41m／s；在法国和德国之间的区域，达55m／s。圣诞节风暴造成欧洲国家大约140人死亡，其他损失包括树木、街道和房屋被毁，电力系统和电话中断时间长达数天，受影响的人数大约为1000万，财产损失大约为80亿美元。由于风暴的极端强度和快速发展速度，欧洲大多数国家的数值预报中心没有对这次剧烈天气提供足够的预警。为此，利用中尺度数值预报系统（RAMS）模拟圣诞节风暴，并与ECMWF分析资料以及实况观测资料进行了对比分析。结果表明，RAMS模式能够准确模拟风暴的主要特性、低气压的演变和位置移动、发展的关键时间点、风暴演化期间的平均风场；模拟的平均风场和气象观测网的观测结果相一致；模拟的风暴移动时间和主要新闻媒体的报道相吻合；模式计算的一些特定地区平均风速的时间趋势显示，在阿尔卑斯山脉地区，无论是上风区还是下风区，风暴的时间都被准确地预测；模拟的第一次风暴最低气压值较实际值偏低。

Numerical Simulation of the 1999 Christmas Day Storms in Europe

The exceptional sequence of storms which affected Western and Central Europe during the Christmas holidays of 1999 is analyzed and the result of an experiment is commented. The second of four main atmospheric depression systems brought a swath of storm-force winds to northern France, gusting more than 170 km/h at Paris Orly Airport, before crossing Germany. The fourth storm produced winds of similar strength along French west coast, and spread a trail of destructive effects along the northern coast of Spain and across many countries bordering the Mediterranean Sea. The maximum wind gusts during the most active phase of the episodes exceeded 150 km/h in the central France, with peaks of more than 200 km/h in an area located between France and Germany. More than 140 people were killed and the list of damages included trees knocked down, streets and houses completely destroyed or seriously damaged, electricity and telephone black-out lasting many days. The effects of the Christmas storms concerned about 10 million people with damages in many European countries quantified in about 8 billion US$. The majority of the Numerical Weather Prediction operational centres failed to provide an adequate warning of the severe weather, due to its extreme intensity and rapid development. In this work, the analysis of the meteorological situation during the storms and of their evolution is provided. The results of a numerical experiment performed with the mesoscale model RAMS are compared to the ECMWF analyses and to synoptic data for the two French storms.