杭州地区气候环境要素对霾天气影响特征分析

The Characteristic Analysis of Climatic and Environmental Factors on the Haze Weather in Hangzhou

利用1998-2010年杭州常规地面气象观测资料、高空探测资料和环境污染物观测资料,对主要天气形势、典型气象要素以及环境污染状况下霾天气特征及形成机制进行了综合分析研究。结果表明:杭州地区高压类型天气形势对霾的产生有重要影响,在气旋和东风带天气形势下较少出现霾天气。霾天气下的大气稳定度主要表现为中性类,出现频率高达54.3%。08时逆温条件下霾出现次数要高于20时;霾出现时平均逆温强度高于非霾时,而平均逆温层厚度、平均最大逆温强度和平均最大逆温层厚度均低于非霾时。污染物PM_(10)、SO_2和NO_2浓度在非霾日比霾日分别下降了33.3%、20.0%和18.2%,随着霾等级的增加,不同污染物浓度也随之增加,颗粒物是造成能见度下降的主要原因之一。此外,杭州特殊的地形环境对霾的发生有一定促进作用。这些结果对于了解杭州霾天气的出现规律以及预警预报工作的开展具有重要意义。

According to routine surface meteorological data, upper air sounding data and environmental pollutant observation data from 1998 to 2010 in Hangzhou, we did a comprehensive analysis of the haze characteristics and formation mechanism under the main synoptic situations, the typically meteorological elements as well as environmental pollution. The results indicate that the high-pressure weather situation has a significant effect on haze in Hangzhou, while cyclone and easterly weather situation are less likely to occurring of haze. Neutral stratification plays a leading role in atmospheric stability under haze weather, the frequency is up to 54. 3%. The frequency of haze under inversion conditions at 08：00 BT is higher than that at 20：00 BT, the average inversion strength under haze is higher than no-haze weather, the inversion thickness, the maximum inversion strength and maximum thickness on average are lower than those of no-haze weather. The concentrations of pollutants of PM10, SO2 and NOz were decreased by 33.3%, 20.0% and 18.2% respectively on no-haze days compared to haze days. With the increase in haze levels, the concentration of different pollutants also increases. Particles is one of the main reasons for reducing visibility. In addition, Hangzhou special terrain environment plays a role in leading to the occurrence of haze. Above results are significant to understand the occurrence of haze weather and develop the alarming and forecasting work.