贵港市污染天气分型及污染气象特征研究

污染天气分型研究对空气质量预报预警等具有重要的意义，基于2015年1月~2018年12月欧洲数值预报中心（ECMWF）再分析资料和国家气象站常规资料，采用聚类分析法按高空及地面天气形势划分了贵港市的污染天气类型，并探讨各天气类型下的污染天气特征和空气质量状况。结果表明，发生大气污染时，按高空(500 hPa)环流形势可分为两槽一脊型、一槽一脊型、副热带高压型，其中两槽一脊发生在秋冬季的频率最高。按地面环流形势可分为冷高压脊底部型、冷高压控制型、冷高压后部型、西南暖低压型、热带气旋型、均压场型共6种类型，并构建天气学模型。其中冷高压脊底部控制下的污染天气天数最多(61天)；但冷高压控制型空气质量最差(AQI为163)，是造成颗粒物(PM2.5/PM10)超标的类型；西南暖低压型次之(AQI为135)；热带气旋型和均压场型常常表现为高温多日照，容易造成O3污染。大气污染发生时环流形势和气象要素表现为大气稳定度升高，水平和垂直扩散条件变差，地面平均风速不超过1.5m/s，相对湿度大于50%，日雨量皆为不超过5mm的零星小雨。

Study on Classification and Pollution Meteorological Characteristics of pollution weather in Guigang City

Abstract: The classification and mechanism of polluted weather are of great significance for air quality forecasting and early warning. Based on the US reanalysis data and ground conventional meteorological data from January 2015 to December 2018, the cluster analysis method was used to classify the types of polluted weather in Guigang City according to the high altitude and ground weather conditions. It also explores the characteristics of polluted weather and air quality under various weather types. It is expected to provide scientific basis for relevant departments to carry out air pollution prevention and control the total pollution source. The results show that when air pollution occurs, it can be divided into two-slot-ridge type, one-slot-ridge type and subtropical high type according to the high-altitude (500 hPa) circulation situation. Two-slot-ridge type occur most frequently in autumn and winter. According to the situation of ground circulation, it can be divided into six types: cold high pressure ridge bottom type, cold high pressure control type, cold high pressure rear part type, southwest warm low pressure type, tropical cyclone type and pressure equalization type, then building a weather models. Among them, the number of polluted weather days under the control of the cold high pressure ridge is the most (61 days). The cold high pressure controlled air quality is the worst (AQI is 163), causing particulate matter (PM2.5/PM10) to exceed the standard. The southwest warm and low pressure air quality is the second most serious (AQI is 135).Tropical cyclone type and pressure equalization field type often show high temperature and multiple sunshine, which is easy to cause O3 pollution.When atmospheric pollution occurs, the circulation situation and meteorological elements show that the atmospheric stability increases. The horizontal and vertical diffusion conditions become worse and the average surface wind speed does not exceed 1.5m/s.By the way, the relative humidity is greater than 50% and the daily rainfall is less than 5mm.