京津冀一次重度雾霾天气能见度及边界层关键气象要素的模拟研究  

A Modeling Study of the Visibility and PBL Key Meteorological Elements during a Heavy Fog-Haze Episode in Beijing-Tianjin-Hebei of China

作　　者：侯梦玲 王宏[2] 赵天良[1] 车慧正[2] 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心/中国气象局气溶胶与云降水重点开放实验室,南京210044 [2]中国气象科学研究院灾害天气国家重点实验室/中国气象局大气化学重点开放实验室,北京100081

出　　处：《大气科学》2017年第6期1177-1190,共14页Chinese Journal of Atmospheric Sciences

基　　金：科技部大气污染专项项目2016YFC0203306;国家重点基础研究发展计划(973计划)项目2014CB441201;国家自然科学基金项目41590874~~

摘　　要：本文利用GRAPES_CUACE大气化学模式对京津冀地区2015年12月重度雾霾过程进行了模拟和评估。京津冀地区能见度和PM2.5模拟值与观测值的对比表明:该模式能较好地模拟京津冀地区能见度和PM2.5的逐日变化情况,但模式存在对伴随着重污染发生的低能见度模拟偏高的问题。以12月5~10日的重度雾霾过程为重点,针对地面风速、边界层高度、相对湿度、PM2.5及其对能见度的影响进行了详细分析,研究结果表明:污染过程中大部分地区过程平均风速低于2 m s-1,边界层平均高度低于600 m,相对湿度较高。模式低能见度模拟偏高可能因为:(1)模式模拟重雾霾时段的PM2.5极大值浓度偏低。(2)模拟相对湿度存在系统性偏低的误差,这一误差对能见度的影响表现为两方面,一是相对湿度会通过影响可溶性气溶胶的吸湿增长过程影响气溶胶质量浓度,导致气溶胶消光系数的计算偏低;二是目前模式中采用的能见度的参数化公式考虑了相对湿度对气溶胶吸湿增长的影响,没有考虑雾滴的直接消光作用。The heavy fog-haze episode occurred in Beijing-Tianjin-Hebei region during December 5-10,2015 was simulated using GRAPES_CUACE（Global/Regional Assimilation and Pr Ediction System coupled with the China Meteorological Administration Unified Atmospheric Chemistry Environment）.Characteristics of wind speeds at the surface,PBLH（Planetary boundary layer height）,relative humidity and PM2.5 concentration as well as their impacts onvisibility were analyzed in detail.The results show that the diurnal variation of visibility and PM2.5 mass concentration inBeijing-Tianjin-Hebei region could be well simulated while the low visibility during the heavy fog-haze pollution wasover estimated.The average wind speed was lower than 2 m s^-1 and the average PBLH was lower than 600 m in mostareas during the fog-haze episode.The overestimation of the low visibility by the model are due to the following reasonsaccording to the simulation analysis.First,the maximum concentration of PM2.5 during the heavy fog haze episode wasunderestimated;second,the simulated relative humidity was lower than observations,which affected the hygroscopicgrowth process of soluble aerosols and the concentration of aerosols,leading to changes in aerosol extinction;and thecurrent parametric formula doesn’t take into consideration the direct extinction of fog-drops.These results indicate thatthe simulation and prediction of surface relative humidity have important impacts on accurate simulation of low visibilityduring heavy fog-haze episodes.

关 键 词：雾霾 PM2.5 能见度 相对湿度 GRAPES_CUACE模式 

分 类 号：P401[天文地球—大气物理学与大气环境]