沪宁高速公路一次复杂性大雾过程的数值模拟试验  

Numerical Simulations of a Highly Complex Fog Event on Shanghai–Nanjing Expressway

作　　者：包云轩[1,2] 丁秋冀[1,2] 袁成松[2,3] 严明良[1,3] 

机构地区：[1]南京信息工程大学江苏省农业气象重点实验室,南京210044 [2]南京信息工程大学应用气象学院,南京210044 [3]江苏省气象科学研究所,南京210008

出　　处：《大气科学》2013年第1期124-136,共13页Chinese Journal of Atmospheric Sciences

基　　金：基金资助国家公益性行业(气象)科研专项GYHY200906037-27;江苏省科技支撑计划BE2010750;江苏省高校优势学科建设工程

摘　　要：为探明高速公路大雾天气的成因和演变规律,揭示雾影响交通能见度的机理,本文根据布设于我国沪宁高速公路沿线的环境气象自动监测系统(AWMS)实测资料和覆盖公路周边地区的常规气象台站观测资料,筛选出2009年11月7日发生在沪宁高速公路上的一次典型复杂性大雾天气过程。在分析天气实况的基础上,应用高时空分辨率的非静力中尺度数值预报模式WRF3.1,结合NCEP0.5°×0.5°气象再分析资料,对该过程进行了数值模拟;利用实测资料对模拟结果进行了验证,并剖析了此次复杂性大雾过程形成的动力、水汽和热力条件。研究表明:(1)本次大雾前后的天气形势相对稳定,江苏地区主要受入海反气旋西南侧东南气流影响,整个大雾过程中地面风力始终微弱,为大雾形成提供了有利的动力条件;(2)模式模拟的由大气液态含水量条件判别的成雾区分布与实测雾区范围基本吻合;(3)模式模拟的能见度与AWMS实测能见度十分接近;(4)本次大雾过程最初是团雾雏形,在夜间辐射冷却作用下,转为辐射雾,之后,来自东南海上的暖湿空气平流进入江苏陆地后,所产生的平流雾雾体与原有辐射雾雾体结合发展为范围更大的辐射平流混合雾;(5)日出后短波辐射增温是此次复杂性大雾雾体得以快速消散的主要原因。The objective of this study is to ascertain the engendering causes and evolving patterns of dense fog weather processes on expressways and to reveal their mechanisms of influencing visibility during transportation. Observed fog data from the automatic weather monitoring system （AWMS） along the Shanghai-Nanjing Expressway in China and that from conventional meteorological stations covering areas near the same region were collected and analyzed for a typical complex fog event that occurred over the expressway on November 7, 2009. Based on analysis of actual weather conditions during the fog event, the Weather Research and Forecasting Model for Version 3.1 （WRF3.1）, a non-hydrostatic mesoscale numerical forecasting model with high spatial and temporal resolutions, was used in conjunction with National Centers for Environmental Prediction （NCEP） 0.5°×0.5° meteorological reanalysis data to simulate a typical fog event. Numerical simulations of several physical variables were verified from the observed data of the fog event data of AWMS. The dynamic and thermodynamic conditions engendering this complex fog event in addition to moisture levels were analyzed. The following were the main conclusions： （1） The atmospheric circulation conditions in Jiangsu Province and its contiguous regions were stable before and during the heavy fog event. These regions were affected by the southeastern stream at the southwestern side of an anti-cyclone system over the Yellow Sea. Moreover, a weak surface wind present during the entire fog process provided favorable dynamic conditions for engendering heavy fog. （2） The simulated distribution areas of the fog masses depicted by the liquid water content （LWC） agreed with observation data. （3） The simulated visibilities were very close to the observed AWMS visibility data. （4） The mixed fog event occurred during 18：00 （BST） November 7 to 08：00 （BST） November 8, 2009. The embryo of this heavy fog event was a local patchy fog that was converted i

关 键 词：沪宁高速公路 复杂性大雾 WRF模式 能见度 数值模拟 

分 类 号：P426.4[天文地球—大气科学及气象学]