宿迁市PM2.5积累机制及重污染天气过程分析

统计宿迁市2017—2021年秋冬季PM2.5数据以及同期常规气象观测资料，基于PM2.5日变化特征，根据15:00—23:00的浓度变化将其分为快速积累、慢速积累、消散三大过程，从积累速率的角度分析了宿迁市PM2.5的积累特征，并将其应用于重污染天气过程下的环流形势与积累速率相关性的探讨。结果表明，发生快速积累过程的平均积累速率为7.14μg·m-3·h-1 ；慢速积累过程平均积累速率为3.27μg·m-3·h-1 ；发生消散过程的PM2.5平均消散速率为5.42μg·m-3·h-1 。PM2.5慢速积累过程中气温高，风速大，湿度小，逆温强度弱，快速积累则与之相反。慢速积累过程的PM2.5潜在源区主要位于苏北地区及北部的山东、河北地区，快速积累过程的PM2.5主要潜在源区则位于西部的安徽、湖北地区。快速积累过程以高空槽后配地面高压前部型为主，慢速积累过程以纬向环流配合地面均压场为主。

Accumulation mechanism of PM2.5 and the causes of serious pollution weather in Suqian city,China

In accordance with statistics of PM2.5 data of Suqian in the autumn and winter of 2017-2021 and the conventional meteorological observation data of the same period and based on the daily variation characteristics of PM2.5, the three major processes of rapid accumulation, slow accumulation, and dissipation were classified according to the concentration changes from 15:00-23:00. The accumulation characteristics of PM2.5 of Suqian was analyzed from the perspective of the accumulation rate, which was applied to the exploration of the correlation between the circulation situation and accumulation rate under the process of heavy pollution weather. The results showed that the average accumulation rate of PM2.5 in the rapid accumulation process was 7.14 ; the average accumulation rate of PM2.5 in the slow accumulation process was 3.27 ; the average dissipation rate of PM2.5 in the dissipation process was 5.42. The slow accumulation of PM2.5 is characterized by high temperature, high wind speed, low humidity, and weak inversion intensity, while the rapid accumulation is the opposite. The potential source areas of PM2.5 during the slow accumulation process are mainly located in northern Jiangsu, Shandong and Hebei, and the main potential source areas of PM2.5 during the fast accumulation process are located in Anhui and Hubei. The fast accumulation process is dominated by the high altitude trough followed by the ground high-pressure front, and the slow accumulation process is dominated by the latitudinal circulation with the homogeneity surface pressure field.