辽东湾西岸热边界层及对大气扩散影响预测

本文应用现场观测结果讨论辽东湾西岸(绥中发电厂环境影响评价区),由于海陆效应影响大气扩散的形式之一、即由局地气团变性所产生的热边界层的发生发展规律。文中应用了漫烟污染模式(1)对研究区热边界层影响下的SO_2地面浓度进行了预测分析。     

复杂地形气象场对污染物浓度空间分布影响的研究

利用WRF模式与多尺度空气质量模式(CMAQ)系统模拟了试验期间(2005年1月30-2月2日)兰州市城区SO2的地面浓度,并根据模拟结果进一步分析了兰州市冬季污染物的空间分布特征。研究结果表明西固区和城关区各有一处污染物高浓度区域;受排放源空间分布和气象场的综合影响,夜间SO2地面污染范围小于日间,夜间污染物地面最大浓度明显高于日间,夜间模拟区域平均值低于日间;水平流场和山谷风环流形成的垂直运动均对污染物地面浓度有明显影响。     

中尺度模式对冬季兰州市低空风场和温度场的数值模拟

利用美国NCAR新一代中尺度模式MM5V3，对山谷城市兰州冬季风场和温度场进行了数值模拟研究。模拟结果与现有理论及观测事实基本一致。表明MM5V3中尺度模式可用于研究山谷城市的大气边界层情况，模式能够较好地模拟山谷城市冬季边界层的风场和温度场特征，模拟结果分析表明，位于河谷盆地内的兰州，冬季近地面风场是山谷风环流和城市热岛环流共同作用的结果，冬季夜间地面流场辐合明显，低空盛行东风，夜间距地300m左右，风向转变为偏西风，白天风向转变高度高于夜间，大约在500m以上；冬季温度场逆温特征明显。     

2006-2012年青岛市空气质量与气象条件的关系

利用2006-2012年青岛市SO₂、NO₂及PM₁₀的监测资料,统计分析3种污染物时空分布特征及污染物平均浓度与气象要素的关系,并分析污染日气象条件变化特征。结果表明：2006-2012年青岛市年平均污染日数为23-33 d;青岛市空气污染主要出现在冬、春两季,主要污染物为PM₁₀。青岛中度以上污染为PM₁₀污染,大多由浮尘天气引起。污染物浓度与云量、降水量和气温呈负相关,与气压呈正相关。冬季大雾易造成空气污染加重,而4-6月海雾则使空气质量提高。弱的地面天气形势和接地逆温层结的存在及持续的烟、霾天气易导致青岛空气污染。     

黑龙江省沙尘天气发生的气候背景和预报方法

对2000～2003年黑龙江省较典型的7次沙尘天气过程进行气候条件和地面天气形势分析,并对沙尘天气影响下哈尔滨地区的空气污染状况特别是颗粒物污染进行了分析。结果表明：持续少雨、高温、春季大风是发生沙尘天气的气候条件;沙尘天气发生时,中等以上污染的地面天气形势有高低压同时发展、强低压发展、春季其它类型鞍形场均值区和弱低压内3种类型;在沙尘天气影响下,哈尔滨地区的颗粒污染物浓度迅速上升,形成中、重度污染。建立了未来24h发生沙尘天气的高空及地面预报模型。     

兰州市空气污染气象条件综合分析

利用兰州市1971～1999年地面气象和探空资料,对影响兰州市污染物浓度变化的风、温、压、湿特性及逆温层、最大混合层厚度的变化特征进行分析,揭示了造成兰州市冬季空气污染特别严重的原因主要是各气象要素及有关污染参数均表现出冬季不利于大气污染物稀释扩散的特征.     

大气物理过程方案对PM2.5预报的敏感性试验

利用WRF-Chem大气化学模式,选择2015年12月中旬发生在我国的大范围空气污染过程,在采用同样化学方案条件下,针对模式中不同物理过程及其参数化方案开展了地面PM_(2.5)预报的敏感性试验。结果表明:该模式能较好展示此次PM_(2.5)污染的演变过程,与实况也较接近,但对青海经宁夏至内蒙的PM_(2.5)高值区出现了漏报现象,这可能是模式外边界未对污染物做更新所致。对地面PM_(2.5)的预报,各物理过程的敏感度不同,边界层(含近地面层)过程的影响要明显大于积云对流及微物理过程的影响,不同的参数化方案会造成不同的预报误差。边界层过程QNSE和与其配套的近地面层方案的组合是预报的较佳组合;而TEMF和与其配套的组合以及ACM2和Pleim-X的组合则不佳。合理的物理过程参数化方案有助于提高PM_(2.5)预报质量。模式预报对排放源也有适应过程,其Spin-up时间较气象要素长。     

气象-气溶胶资料联合同化对秋季PM2.5浓度模拟的影响研究

相比冬季大范围静稳条件下的污染堆积过程,秋季气象条件更加复杂和局地化,气象条件模拟不确定性给秋季气溶胶模拟带来了更大难度,且目前研究较少考虑气象-气溶胶因素在线模拟和联合同化。使用WRF/Chem模式和格点统计差值（GSI）三维变分同化系统,2015年10月进行了为期1个月的气象-气溶胶资料联合同化及模拟试验,并基于此讨论了气象-气溶胶资料联合同化对秋季PM_2.5浓度模拟的影响。结果表明,WRF/Chem模式可以模拟出秋季污染天气过程,但对华北平原和中东部地区存在高估、西北部存在低估现象;同化地面PM_2.5浓度观测资料可以改进对PM_2.5浓度的模拟,上述两个地区的偏差均得到订正,6 h预报偏差均降低至6 μg/m3以内;重点针对华北地区的分析表明,秋季PM_2.5污染过程与特殊气象条件（湿度升高、风场辐合、区域输送）密切相关,因此在地面PM_2.5观测资料同化基础上增加常规气象资料同化,能进一步提高对华北平原气象-污染过程的表达,PM_2.5浓度预报相关系数从0.86提高至0.89。气象-气溶胶联合资料同化能更加准确地模拟秋季气溶胶污染过程,为更好地开展污染成因和在气象预报框架下开展气象-气溶胶相互影响研究提供了基础。      

一次雾霾天气过程的污染影响因子分析

利用常规天气资料、自动气象站资料、观象台风廓线雷达资料及污染资料,分析了2005年11月2-5日发生在北京的一次持续雾霾天气过程中中低空扰动、山谷风以及城市热岛对PM10浓度的影响。结果表明:PM10对中低空的扰动很敏感,且扰动越靠近地面,层次越厚,污染指数下降越明显;城区PM10浓度明显高于清洁对照站定陵,但北京地方性山谷风对城郊浓度日变化有明显影响,当谷风加强时,定陵站浓度接近城区并有可能高于城区浓度,谷风有对城区重污染向郊区输送的作用;雾霾天气下热岛效应显著,热岛对PM10浓度的影响相对气象条件和人类活动的影响来说很小。     

城市空气污染天气统计短期预报方法

近几年,苏联许多城市普遍采用空气污染天气统计预报方法制作城市空气污染短期预报。开展此类预报是很有必要的。因为通过预报,使我们有可能对城市空气中的污染状况作出总的估计,以便估计污染的危险程度,从而采取措施防止污染。同时,有必要对每一种污染物造成的空气污染进行定量预报。目前,根据大气扩散模式,计算点源污染浓度的方法研究得比较多。但此类计算方法局限在有限的点源范围内使用,且密切依赖于污染源参数及排放物资料的准确性。上述资料,目前在大城市条件下还得不到。大气扩散与湍流参数的不可预报性,是目前这方法中不可克服的困难。鉴于高浓度污染与气象条件之间存在相当密切的关系,因而有可能从气象角度来解决空气污染定量预报的问题。最近,有人尝试根据预报的气象参     

A FUMIGATION DIFFUSION MODEL DURING THE MOUNTAIN-VALLEY WIND SHIFT PERIOD

The fumigation during the mountain-valley wind shift has been first identified as a special type of pol-lutant diffusion using the monitoring measurements of Dukou,Southwest Sichuan,China.Such a pheno-menon occurs frequently all year around but summer,particularly in winter months.A new model for thefumigation during the mountain-valley wind shift period is developed that allows satisfactory explanation ofthe fact.Analyses indicate that the model can more accurately predict not only the high concentration ofPollutants but the time and locality of the occurrence as well.The ground concentration of SO_2 during fumigation is several times up to over a decade higher thanthe daily mean for the whole region,one of the main contamination processes that affect the air quality ofthe city.The medel analyses provide a basis for more effective prediction of the quality and precautionstudy against the disaster.     

2007年冬季沈阳典型大气污染源PM10排放模拟

选取沈阳市区9个典型的大气污染源冬季的PM10排放浓度资料,利用MM5耦合CALPUFF对2007年12月至2008年2月沈阳城市区域气象场和排放PM10浓度分布进行月平均数值模拟.结果表明:冬季沈阳地区受高压控制,北风较强,并经过增强、减弱的过程,多呈现对大气污染物扩散不利的天气形势.高空为偏西风且风速较大时,地面和...     

Air quality modeling for the city of Graz

Summary Graz, a historical grown city in the south-east of Austria, sometimes faces problems with air pollution, mainly during wintertime. The old part of the city is the largest residentially used historical downtown in Central Europe. Due to its geographical position at the southeastern edge of the Alps, Graz often has weather situations with calm winds and strong inversions between October and March. The local wind system is marked by wind shears: near the surface, cold air flows in from the south, while in higher altitudes warm air from the north flows over the basin of Graz. During these winterperiods with mighty inversions air quality values exceed the threshold limits. The reason is that the old structure of the downtown area with narrow streets and a lot of old domestic heating systems in many of the old buildings causes relatively high pollution levels. In the winter of 1988/89, the NO₂ threshold values for smog-alarm (0.8 mg/m³, 3-h mean value) were exceeded several times at three air quality monitoring stations in the city of Graz. Therefore, a research project was initiated with the aim to find out the reasons for the bad air quality. The project comprised the setting up of an emission inventory as well as meteorological measurement campaigns and numerical simulations concerning the pollution dispersion in the area of Graz. The following report will try to show the interaction of the emission inventory on one hand and the determinations of flow conditions and pollutant dispersion on the other hand in order to analyze the air quality in the city. The emission inventory contains the emissions of air pollutants in a high temporal and spatial resolution. Before determining the surface flow fields, the meteorological conditions leading to the high pollution values were analyzed. After that, the boundary conditions were defined with the help of tethered balloon measurements. With these boundary conditions, quasi-steady-state flow fields were simulated. The dispersion of pollutants was calculated in a transient form using the stored flow fields. Conversion of pollutants was determined with the help of a parameterized version of the Eschenroeder-Martinez reaction mechanism. The period of winter 1990/91 with the highest pollution concentration was simulated to validate this model. The results show that the simulated and measured values of CO, NO and NO₂ correspond well with each other in the centre of the city, while the correspondence is not as good in the outskirts of the city were lower pollution levels are observed. It turned out that the suggested methodology is well suited for analyzing winter situations with high pollution levels.With 10 Figures     

Meteorological prerequisites of formation of severe wintertime air pollution episodes in Moscow

Large-scale and local weather conditions during severe wintertime air pollution episodes in the Moscow megalopolis are analyzed. Concentrations of CO, NO, and NO₂ obtained from the automated network of the atmosphere pollution control are used as tracers for atmospheric processes in the urban atmospheric boundary layer. It is shown that a high surface air pollution level in the city is formed at a weak wind in the lower atmosphere and only in the presence of a surface or low elevated temperature inversion. Temperature contrasts in the urban heat island generate the circulation that promotes air pollution in megapolis regions remote from large emission sources. It is supposed that in case of severe frosts the amount of anthropogenic heat in the megapolis sharply increases, promoting active turbulent mixing, thus preventing pollution accumulation in the surface air.     

CALPUFF模型在合肥地区SO2大气环境容量测算中的应用

在对合肥地区污染源调查的基础上,利用CALPUFF模型模拟了合肥地区大气污染物SO₂质量浓度场,通过与现场监测结果对比分析了模型的适用性,并根据模拟结果研究了不同排放源对合肥地区大气污染的贡献情况,建立了大气污染物传递矩阵;通过综合考虑城市区域的大气扩散能力、污染源贡献和大气环境质量目标等,采用线性规划模型测算了合肥市的大气环境容量.     

2007年冬季沈阳典型大气污染源PM10排放模拟

选取沈阳市区9个典型的大气污染源冬季的PM10。排放浓度资料,利用MM5耦合CALPUFF对2007年12月至2008年2月沈阳城市区域气象场和排放PM10。浓度分布进行月平均数值模拟。结果表明：冬季沈阳地区受高压控制,北风较强,并经过增强、减弱的过程,多呈现对大气污染物扩散不利的天气形势。高空为偏西风且风速较大时,地面和高空有明显的风向和风速的切变,切变有增强和减弱的变化。2007年冬季沈阳市区域月平均大气污染最严重的是2月,污染物分布主要集中在南部、东南部地区,南部地区大气污染最为严重。PM10。浓度分布的范围与风场、地形有直接的关系。地势平坦、风速大时,污染物扩散范围大,污染物浓度小;地势不平、风速小时,污染物扩散范围小,污染物浓度大。     

南昌市一次连续空气污染过程的气象条件分析

2004年12月8—16日南昌市出现了一次连续空气污染过程。利用城市空气污染观测资料和气象常规观测资料,从天气形势和主要气象要素两个方面,对此次空气污染过程进行了分析。结果表明,此次连续空气污染事件都是出现在风速小、无雨和有雾或霾的气象条件下,高空主要为高压脊的形势或是处在西风槽底的平直气流中,低层大气稳定,中层大气增温明显;地面形势主要为地面高压脊、高压底部或是倒槽前部,地面有弱冷空气南下时不一定能改变污染状况。极厚、极强的逆温层和极小风速的持续存在是造成污染物高浓度最重要的气象条件。此外,地形也是影响南昌市空气质量水平的因素之一。     

大气污染系数概念的辩正及其在甘肃部分地区的初步应用

1.引言工业污染源对环境的影响是长期的,在环境影响分析和城镇工业规划设计中,需要依据气候资料来分析污染浓度变化的长期统计规律,这就涉及到空气污染气候学的论题。影响空气污染的气象因子是很多的:如风向、风速、大气稳定度、混合层厚度、降水等。但不论哪类空气污染问题,风向、风速总是重要的因子,风向指示污染物的输送方向,风速决定污染物的稀释和输送速率。     

Temporal evolution of winter smog within a nocturnal boundary layer at Christchurch, New Zealand

Summary In July 2000 (South Hemisphere winter), the Christchurch Air Pollution Study (CAPS2000) was performed in order to establish a comprehensive data set for documentation and analysis of nocturnal winter smog conditions in the Christchurch area. Field activities included meteorological surface measurements, tethersonde ascents, radiosoundings and sodar measurements. Air pollutant monitoring included CO, NO, NO_x, O₃, PM₁₀, PM_2.5, and black carbon measurements near the surface, and for the first time vertical CO-profile measurements in the nocturnal boundary layer up to 100 m height. A prerequisite for nocturnal winter smog conditions is the evolution of stable stratification before the evening traffic and domestic heating reach a maximum. When stable stratification persists during domestic heating and road traffic in the morning, a second pronounced maximum of air pollutants evolves at around 0800 NZST. The meteorological measurements also revealed a complex nocturnal surface wind field, dominated by drainage winds from the Port Hills to the south and from the Canterbury Plains to the west of the Christchurch city area. A resulting convergence zone forms over the central parts of the city and is accompanied by low wind speeds. The position of the convergence zone varies during the night. These low winds over the city centre, in conjunction with stable stratification, favour the accumulation of air pollutants in the lowest tens of metres. The nocturnal winter smog situation ends with the erosion of the surface inversion at about 1100 NZST. It is shown from analysis of the vertical CO profiles that the level of air pollution in the Christchurch area depends on the height of the stable nocturnal boundary layer, which itself is governed by variations in the local wind systems.