半干旱地区气溶胶散射和吸收特性的观测研究     

王振海  张武  史晋森  黄建平  陈艳  田磊  向涛 《高原气象》2012,31(5):1424-1431

利用兰州大学半干旱气候和环境观测站SACOL（Semi-Arid Climate and Environment Observatory of Lanzhou University）2007年11月1日-2008年10月31日AE-31黑碳仪和2007年8月1日-2008年7月31日M9003积分浊度仪的连续观测资料,对该地区气溶胶散射和吸收特性的变化特征进行了分析。结果表明,该地区气溶胶年平均散射系数为158.86M.m-1,吸收系数为14.11M.m-1,520nm单次散射比为0.83;散射系数和吸收系数的年变化呈单峰型,峰值分别出现在12月和11月;采暖期内日变化呈双峰型,非采暖期内近似表现为单峰型。在沙尘天气条件下,散射系数和吸收系数分别增大了103.8%和88.5%。结合同期APS-3321粒子谱仪的相关观测资料分析得出,无论是粒子数浓度还是质量浓度,与散射系数和吸收系数的相关系数均在0.8以上。  相似文献   

北京PM₁中的化学组成及其控制对策思考   总被引：5，自引：0，他引：5       下载免费PDF全文

张小曳  张养梅  曹国良 《应用气象学报》2012,23(3):257-264

通过分析北京城区2007年夏季和秋季、2008年冬季和春季4个季节PM₁中硫酸盐、硝酸盐、铵盐、有机物和黑碳等气溶胶化学组成,结合对我国及全球主要区域PM₁₀中上述气溶胶组分及矿物气溶胶组成的评估,发现因受干旱区产生的沙尘和城市逸散性粉尘的共同影响,整个亚洲大陆,尤其是我国的矿物气溶胶浓度与欧美国家城市区域气溶胶总和的平均值相当或更高。我国在重视控制PM_2.5等细粒子污染的同时,不应忽视对PM_2.5~PM₁₀之间粗粒子的控制力度;北京城区春、夏、秋、冬的PM₁平均质量浓度分别约为94,74,66 μg·m-3和91 μg·m-3,全年平均约为81 μg·m-3,其中有机物气溶胶约占41%,硫酸盐占16%,硝酸盐占13%,铵盐占8%,黑碳和氯化物分别占11%和3%,细矿物气溶胶约贡献7%。对于PM_2.5污染的控制,关键是消减PM₁中主要气溶胶粒子的排放与转化,其中对有机物的控制更为重要,尽管对于北京而言进一步污染控制的难度已经很大。从科学上来说,即使我国的控制措施能百分之百实现,也很难稳定地达到欧美国家的空气质量水平,因为我国本底矿物气溶胶的浓度较高。应进一步评估各项控制措施的适用性,并制定考虑我国人群健康状况的PM_2.5空气质量标准。  相似文献   

2007和2008年夏季北京奥运馆大气PM10与PM2.5质量浓度变化特征     

李雪  刘子锐  任希岩  李昕  王跃思 《南京气象学院学报》2012,35(2):197-204

为了监测北京奥运主场馆附近大气颗粒物的污染状况以及评估奥运污染源减排措施对北京大气颗粒物质量浓度变化的影响,利用颗粒物在线监测仪器TEOM于2007年和2008年夏季,在奥运主场馆附近的中国科学院遥感应用研究所办公楼楼顶对大气颗粒物PM10和PM2.5进行了连续同步观测。结果表明,2007年夏季监测点附近大气PM10与PM2.5质量浓度的平均值分别为153.9和71.2μg.m-3,而2008年夏季PM10与PM2.5质量浓度的平均值分别为85.2和52.8μg.m-3。与奥运前一年同时段相比,奥运时段大气PM10和PM2.5的质量浓度分别下降44.5%和25.1%。对比分析奥运前后的2次典型污染过程发现,空气相对湿度的增加和偏南气流输送的共同影响易造成大气颗粒物的累积增长,而降雨的湿清除作用和偏北气流则会使大气颗粒物浓度迅速降低。在相近的气象条件下,奥运前后的污染过程中,大气细粒子的日均增长速率分别为25.1和13.9μg.m-3.d-1,而大气粗粒子的日均增长速率分别为20.8和2.2μg.m-3.d-1,奥运时段污染累积过程中大气粗、细粒子的增长速率分别显著低于和略低于奥运前同时段污染过程中颗粒物的增长速率。污染源减排措施的实施是奥运期间大气颗粒物质量浓度降低的主要原因,从控制效果来看,奥运期间实施的污染源减排措施对大气粗粒子的控制效果明显好于大气细粒子。  相似文献   

秸秆燃烧排放对北京及其周边地区PM2.5浓度影响的数值模拟     

徐敬  寇星霞  李梓铭 《气候与环境研究》2018,23(5):587-595

采用卫星监测的火点燃烧排放数据,利用区域化学传输模式WRF-Chem模拟分析了2017年5月华北地区细颗粒物(PM2.5)质量浓度分布,通过生物质燃烧排放源(华北区域以秸秆燃烧为主)开关的敏感性试验定量计算了燃烧排放对北京及其周边地区PM2.5质量浓度的影响。卫星监测结果显示,2017年5月华北地区有大量的秸秆焚烧现象,对该地区空气质量造成一定影响的燃烧天数为20 d,占全月总日数的65%左右。数值模拟结果表明:该地区秸秆燃烧排放导致PM2.5浓度升高的区域集中在华北平原农作物产区,其分布位置与卫星监测的火点分布吻合。秸秆燃烧导致这些地区PM2.5浓度月平均值上升幅度普遍超过3 μg/m~3,高值区超过了11 μg/m~3,上升比例可达10%以上;此外,来自华北平原及长三角地区的燃烧排放对北京(特别是东南部地区)污染物浓度的影响是不容忽视的,其中河南、山东、天津等地的秸秆燃烧在合适风场的作用下会严重影响北京,可导致丰台及通州等地PM2.5小时浓度上升超过17 μg/m~3,上升幅度超过40%。  相似文献   

成都典型秸秆燃烧季节PM2.5中化学成分研究     

瞿群  杨毅红  宋丹林  曲兵  周来东 《气候与环境研究》2016,21(4):439-448

采集2012年春季和秋季成都城区的PM2.5(空气动力学当量直径小于等于2.5μm的颗粒物,即细颗粒物)样品,分析得到水溶性离子、有机碳(OC)和元素碳(EC)等化学成分。结果表明,春季和秋季PM2.5的浓度分别为101±64μg m~(-3)和88±30μg m~(-3),是环境空气质量标准(GB3095-2012)日均值的1.3倍和1.2倍。基于K~+、OC/EC(OC浓度/EC浓度)和K~+/EC(K~+浓度/EC浓度)指标判别生物质燃烧事件,结果发现春、秋季生物质燃烧期间PM2.5中OC、EC和K~+、Cl~-等成分明显高于非生物质燃烧期;SO_4~(2-)、NH_4~+、Ca~(2+)、Mg~(2+)、NO_3~-、Na~+等其它水溶性离子浓度在生物质燃烧期均有不同程度升高。春、秋季生物质燃烧期间OC浓度分别是非生物质燃烧期的4.2倍和1.8倍,EC为非生物质燃烧期的2.3倍和2.3倍。K~+和Cl~-浓度在春季生物质燃烧期超过平均值的3倍,在秋季生物质燃烧期超过平均浓度的0.8倍和0.9倍。  相似文献   

Geochemistry of regional background aerosols in the Western Mediterranean     

J. Pey  N. Prez  S. Castillo  M. Viana  T. Moreno  M. Pandolfi  J.M. Lpez-Sebastin  A. Alastuey  X. Querol 《Atmospheric Research》2009,94(3):422-435

The chemical composition of regional background aerosols, and the time variability and sources in the Western Mediterranean are interpreted in this study. To this end 2002–2007 PM speciation data from an European Supersite for Atmospheric Aerosol Research (Montseny, MSY, located 40 km NNE of Barcelona in NE Spain) were evaluated, with these data being considered representative of regional background aerosols in the Western Mediterranean Basin. The mean PM₁₀, PM_2.5 and PM₁ levels at MSY during 2002–2007 were 16, 14 and 11 µg/m³, respectively. After compiling data on regional background PM speciation from Europe to compare our data, it is evidenced that the Western Mediterranean aerosol is characterised by higher concentrations of crustal material but lower levels of OM + EC and ammonium nitrate than at central European sites. Relatively high PM_2.5 concentrations due to the transport of anthropogenic aerosols (mostly carbonaceous and sulphate) from populated coastal areas were recorded, especially during winter anticyclonic episodes and summer midday PM highs (the latter associated with the transport of the breeze and the expansion of the mixing layer). Source apportionment analyses indicated that the major contributors to PM_2.5 and PM₁₀ were secondary sulphate, secondary nitrate and crustal material, whereas the higher load of the anthropogenic component in PM_2.5 reflects the influence of regional (traffic and industrial) emissions. Levels of mineral, sulphate, sea spray and carbonaceous aerosols were higher in summer, whereas nitrate levels and Cl/Na were higher in winter. A considerably high OC/EC ratio (14 in summer, 10 in winter) was detected, which could be due to a combination of high biogenic emissions of secondary organic aerosol, SOA precursors, ozone levels and insolation, and intensive recirculation of aged air masses. Compared with more locally derived crustal geological dusts, African dust intrusions introduce relatively quartz-poor but clay mineral-rich silicate PM, with more kaolinitic clays from central North Africa in summer, and more smectitic clays from NW Africa in spring.  相似文献   

Characteristics of organic and elemental carbon in PM_2.5 samples in Shanghai, China   总被引：11，自引：0，他引：11  

Yanli Feng  Yingjun Chen  Hui Guo  Guorui Zhi  Shengchun Xiong  Jun Li  Guoying Sheng  Jiamo Fu   《Atmospheric Research》2009,92(4):434-442

Shanghai is the largest industrial and commercial city in China, and its air quality has been deteriorating for several decades. However, there are scarce researches on the level and seasonal variation of fine particle (PM_2.5) as well as the carbonaceous fractions when compared with other cities in China and around the world. In the present paper, abundance and seasonal characteristics of PM_2.5, organic carbon (OC) and elemental carbon (EC) were studied at urban and suburban sites in Shanghai during four season-representative months in 2005–2006 year. PM_2.5 samples were collected with high-vol samplers and analyzed for OC and EC using thermal-optical transmittance (TOT) protocol. Results showed that the annual average PM_2.5 concentrations were 90.3–95.5 μg/m³ at both sites, while OC and EC were 14.7–17.4 μg/m³ and 2.8–3.0 μg/m³, respectively, with the OC/EC ratios of 5.0–5.6. The carbonaceous levels ranked by the order of Beijing > Guangzhou > Shanghai > Hong Kong. The carbonaceous aerosol accounted for  30% of the PM_2.5 mass. On seasonal average, the highest OC and EC levels occurred during fall, and they were higher than the values in summer by a factor of 2. Strong correlations (r = 0.79–0.93) between OC and EC were found in the four seasons. Average level of secondary organic carbon (SOC) was 5.7–7.2 μg/m³, accounting for  30% of the total OC. Strong seasonal variation was observed for SOC with the highest value during fall, which was about two times the annual average.  相似文献   

Size-resolved aerosol chemical concentrations at rural and urban sites in Central California, USA     

Judith C. Chow  John G. Watson  Douglas H. Lowenthal  Karen L. Magliano 《Atmospheric Research》2008,90(2-4):243-ICNAA07

Aerosol size distributions were measured with Micro Orifice Uniform Deposit Impactor (MOUDI) cascade impactors at the rural Angiola and urban Fresno Supersites in California's San Joaquin Valley during the California Regional PM₁₀/PM_2.5 Air Quality Study (CRPAQS) winter campaign from December 15, 2000 to February 3, 2001. PM_2.5 filter samples were collected concurrently at both sites with Sequential Filter Samplers (SFS). MOUDI nitrate (NO₃⁻) concentrations reached 66 μg/m³ on January 6, 2001 during the 1000–1600 PST (GMT-8) period. Pair-wise comparisons between PM_2.5 MOUDI and SFS concentrations revealed high correlations at the Angiola site (r > 0.93) but more variability (r < 0.85) at the Fresno site for NO₃⁻, sulfate (SO₄⁼), and ammonium (NH₄⁺). Correlations were higher at Fresno (r > 0.87) than at Angiola (r < 0.7) for organic carbon (OC), elemental carbon (EC), and total carbon (TC). NO₃⁻ and SO₄⁼ size distributions in Fresno were multi-modal and wider than the uni-modal distributions observed at Angiola. Geometric mean diameters (GMD) were smaller for OC and EC than for NO₃⁻ and SO₄⁼ at both sites. OC and EC were more concentrated on the lowest MOUDI stage (0.056 µm) at Angiola than at Fresno. The NO₃⁻ GMD increased from 0.97 to 1.02 µm as the NO₃⁻ concentration at Angiola increased from 43 to 66 µg m^− 3 during a PM_2.5 episode from January 4–7, 2001. There was a direct relationship between GMD and NO₃⁻ and SO₄⁼ concentrations at Angiola but no such relationships for OC or EC. This demonstrates that secondary aerosol formation increases both concentration and particle size for the rural California environment.  相似文献   

香港能见度、大气悬浮粒子浓度与气象条件的关系   总被引：10，自引：2，他引：8  

梁延刚  胡文志  杨敬基 《气象学报》2008,66(3):461-469

利用2005年赤角能见度及东涌悬浮粒子(PM2.5)浓度的每小时数据,发现PM2.5 浓度与能见度(撇除雨雾及相对湿度≥95%的个例)呈倒数关系,相关系数约为0.8.此外,出现低能见度(能见度低于8 km,而雨雾及相对湿度≥95%的个例不计)的每月总时数与月平均PM2.5浓度都呈现相类似的季节趋势,即冬季较高,夏季较低.利用HYSPLIT作反轨迹图分析显示这现象跟影响香港的空气来源有关.来自内陆的轨迹中,出现低能见度的日平均时数及日平均PM2.5的浓度,分别远高于来自海洋的轨迹.文中还分析了一个有热带气旋接近本港的个例,论证气象条件对能见度及PM2.5浓度的重要性.  相似文献   

二维离散小波变换在磁测资料处理中的应用   总被引：3，自引：0，他引：3  

李志华  张玲玲  孙长玉  白琨  时皓 《物探与化探》2009,33(1):91-98

恰功铁矿是近几年新发现的矿山,矿体的形态、大小、走向、位置、产状、边界等几何特征还没有清楚的认识。为了弄清这些问题,笔者通过小波多尺度分析理论模型数据和实测数据进行分解处理,对比了向上延拓和小波多尺度分析方法在磁测资料处理中的应用效果,证明了磁异常小波多尺度分解方法对矿山的深部找矿具有积极的作用。  相似文献