成都冬季PM2.5污染天气形势的客观分型研究

Study on an Objective Synoptic Typing Method for Air Pollution Weather in Chengdu During Winter

文章利用2013-2018年冬季ERA-interim再分析资料,以及同期空气污染资料、地面常规气象观测资料和探空资料,采用PCT(principal component analysis in T-mode)客观分型方法对成都冬季海平面气压场进行天气分型,并探究冬季以及各月份不同天气型对应的空气污染状况及污染气象参数分布特征,进而从污染气象学的角度揭示重污染潜势天气型的气候特征。结果表明:冬季海平面气压场共对应9种天气类型,其中,6型(准鞍型场型)和9型(冷锋前部型)为2类重污染潜势天气型,冬季对应的PM2.5均值浓度分别为194.3和173.2μg/m3;而1型(川西高压前部型)为清洁天气型,对应的PM2.5均值浓度为73.2μg/m3。重污染潜势天气型对应的边界层结构呈现出稳定能量大、混合层厚度和通风系数均最小的静稳天气特征,其能够反映大气污染潜势。该研究可为盆地地区空气污染潜势预报及大气重污染预报预警的客观化、自动化提供科学依据和技术支持。

PCT(principal component analysis in T-mode) objective synoptic typing method was used to identify the synoptic types in Sichuan Basin of China during winter based on sea surface pressure fields from ERA-Interim reanalysis dataset during 2013 to 2018. Combined with air pollution data, conventional meteorological observations and sounding data, the characteristics of air pollution and the corresponding air pollution meteorological parameters in winter with different synoptic types were studied, and the climatic characteristics of heavy pollution potential types from the perspective of air-pollution meteorology were also revealed. The results showed that there are mainly 9 synoptic types, of which Type 6(quasi saddle field type) and Type 9(cold front type) are two typical types of heavy pollution potential weather, with the PM2.5 mean concentration in winter as 194.3 and 173.2μg/m3 respectively, while Type 1(Western Sichuan high pressure front type) is clean weather, with the PM2.5 mean concentration as 73.2μg/m3. The boundary layer structure corresponding to heavy pollution potential weather pattern shows the characteristics of static and stable weather with large stable energy, small mixing layer thickness and ventilation coefficient, which can reflect the potential of air pollution. This research can provide scientific basis and technical support for the objectification and automation of air pollution potential prediction and air heavy pollution prediction and early warning in the basin area.