广东四大区域污染过程特征与影响天气型分析

Characteristics and analysis on regional pollution process and circulation weather types over Guangdong Province

根据广东统计年鉴将广东省划分为粤东、粤西、粤北、珠三角四大区域,利用广东省101个环保国控站点2014—2016年期间的AQI六要素与广东省86个地面气象观测站的逐日能见度、相对湿度等资料,在对"区域污染过程"进行定义的基础上,分区域诊断典型污染天气过程,并对影响天气型及特征进行分析.结果表明:广东省四大区域污染过程具有显著协同性,区域污染可归类为6种影响天气型.量化分析表明区域污染过程与区域灰霾过程基本吻合,PM_(2.5)日均最大值均达到中度污染及以上(>115μg·m^(-3)).整体区域污染过程影响天气型分类统计表明:珠三角和非珠三角PM_(2.5)易污染天气型中冷高变性出海形势占比超5成;珠三角O_3易污染天气型中副高、台风外围及两者叠加型占比超6成;珠三角NO_2易污染天气型中冷高出海型占比近7成.重污染影响天气型统计表明:区域PM_(2.5)重污染过程主要影响天气型为冷高压变性出海型;区域中度至重度O_3污染过程(集中在珠三角)主要影响天气型为副高、台风外围及两者叠加型;就天气型特征而言,单纯副高控制形势下,副高异常强盛;单纯台风外围形势下,台风强度为强台风至超强台风;副高叠加台风时,华南上空为大陆副高控制.广东地区近年高PM_(2.5)(与低能见度)污染过程逐年减少,但全省臭氧污染呈增加态势,尤其珠三角区域中度至重度O3污染过程次数同比明显增加,极端过程出现概率加大,尤其在秋季副高异常强盛,同时叠加台风外围下沉气流时,可预先根据影响天气型预报,实施珠三角重点区域联防联控预案措施.

With six elements of AQI from 101 national environmental monitoring stations and daily visibility and relativity humidity data from 86 meteorological stations across Guangdong province from 2014 to 2016,regional typical pollution processes were diagnosed based on the definition of＂regional pollution process＂. Furthermore,characteristics of each type of pollution process and atmospheric circulations were analyzed. Results showed that each regional pollution process has significant synergistic effect and low visibility was closely correlated with air pollution（ PM2.5 115 μg·m^-3）. Ingeneral,PM2.5 pollution was mainly accompanied by Cold High Pressure Moving to Sea weather system（ over 50%）; O3 pollution was dominated by synoptic systems like Subtropical High,Typhoon Periphery and the combinations of both（ over 60% in total）. NO2 pollution was typically affected by Cold High Pressure Moving to Sea（ nearly 70%） in the Pearl River Delta region（ PRD）. With regard to severe pollutions,High Pressure Moving to Sea was the primary influenced weather pattern of severe PM2.5 regional pollution. Subtropical High,typhoon periphery and their superposition were the primary influenced weather patterns in regional high ozone pollution processes（ PRD）. In recent years,due to the efforts of regional joint prevention and emission control,high PM2.5（and low visibility） events decreased. However,O3 concentrations are showing an increasing trend,with more O3 polluted events occur. We suggest that regional emission control measures could be implemented in advance based on the forecast of circulation weather types.