福州市灰霾气象要素场特征分析

Analysis of Haze Meteorological Fields in Fuzhou

利用1988-2007年常规观测资料、地面图5、00 hPa高空图资料,分析了福州市灰霾的时间分布,冬、夏半年霾日气象要素场和稳定度因子特征。结果表明：福州市灰霾年变化呈明显上升趋势;月分布呈单峰型,高发期在12、1月;冬半年14：00,夏半年08：00灰霾发生几率最高。冬半年灰霾多出现在冷空气减弱后,地面气压持续下降,温度不断上升,风速弱,湿度大,充分回暖后的天气下,对应地面天气形势有变性高压后部和底部、锋前暖区、地面倒槽;少数出现在冷空气入侵,地面气压上升,温度下降,湿度较小的天气下,对应地面天气形势为大陆冷高压。夏半年灰霾多出现在高温、干燥、大气层结稳定的清晨,对应500 hPa天气形势为副热带高压、副热带高压边缘、地面弱倒槽,以及少量台风外围控制下干热的下沉气流里。

Based on the routine observation synoptic charts and the synoptic charts at 500 hPa from 1988 to 2007, the temporal distribution, meteorological fields, and the stability factor of haze days during spring and summer are analyzed. The results indicate that the annual haze days increased, and the monthly distribution showed a single peak pattern with high values in December and January. There is a highest probability of haze at 14：00 in winter half year and at 08：00 in summer half year. The haze events in winter half year often occur under the weather condition of weakened cold air, decreased surface pressure, increased temperature, low wind velocity and high humidity. The correlative weather systems include the back of the denatured high, the warm sector ahead of fronts, and the ground inverse trough. Occasionally, haze events happened along with the inrush of cold air with the increasing pressure and decreasing temperature and low humidity, and the correlative weather system is the land cold high. The haze events in summer half year often happened in the morning with high temperature, low humidity and stable atmosphere. The influencing systems （500 hPa） include the subtropical high, the edge of the subtropical high, the weak ground inverse trough, and the dry-hot descent flow controlled by a typhoon.