共查询到18条相似文献，搜索用时 107 毫秒
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气溶胶粒子的吸湿增长对区域环境、气象与辐射收支都有巨大影响,精确的气溶胶吸湿特性观测对描述气溶胶吸湿增长特性,以及研究气溶胶对气候环境影响,拓展卫星气溶胶产品的应用有非常重要的意义。本研究提出一种基于常规气象观测（能见度、相对湿度）和空气质量观测（PM2.5浓度,即空气动力学当量直径小于等于2.5 μm的颗粒物浓度）相结合的气溶胶吸湿增长估算方法,在此基础上对浙江地区气溶胶吸湿特性的时空变化影响因素进行了探讨。研究发现,沿海的温州瓯海站的吸湿增长能力最高,长三角典型城市环境的杭州和睦小学站的吸湿增长能力次之,而地处较为洁净内陆的衢州实验学校站的吸湿增长能力最低。在时间变化中,同一站点不同湿度条件的吸湿增长变化趋势相同,温州瓯海站的吸湿性变化最为剧烈,杭州和睦小学站的吸湿性变化次之,衢州实验学校站变化较为平缓。本研究表明,浙江地区的气溶胶吸湿增长特性存在较大的时空差异,基于本方法能够在较大的时空范围内描述气溶胶的吸湿增长特性,为有限的精密观测提供重要补充。 相似文献
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大气气溶胶吸湿性质国内外研究进展 总被引：14，自引：1，他引：13
大气气溶胶的吸湿性质是联系气溶胶微物理、化学参数的桥梁和纽带之一,更是气溶胶基本光学性质的决定性参数之一,因此研究气溶胶吸湿性质在整个大气气溶胶科学研究中处于基础地位。对气溶胶吸湿性质的研究意义、研究方法与技术、主要研究结论做了系统回顾,并指出该研究领域存在的不足并对未来的研究方向做出展望。众多研究者从实验室分析、外场实验、数值模拟3个方面来研究颗粒物的吸湿性质,研究表明大气气溶胶的吸湿性质对研究大气能见度、大气辐射强迫具有重要影响。国内对大气气溶胶吸湿性质的研究数量偏少,研究方法单一,在国内广泛开展气溶胶吸湿性质的研究非常必要。 相似文献
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应用多种化学组分气溶胶的绝热气块分档模式,对2008年春季黄山地区气溶胶吸湿增长特性进行了模拟分析.结果表明:黄山地区气溶胶吸湿增长因子f的大小与粒子半径、相对湿度、粒子化学组分、上升速度及上升高度密切相关,且小粒子吸湿增长比大粒子显著.吸湿增长因子与相对湿度呈正相关,相对湿度越接近粒子的临界饱和比,吸湿增长因子变化越显著.可溶性有机气溶胶,通过增加溶液中溶质的百分比来影响临界饱和比,使吸湿增长因子增大.若不考虑不可溶粒子的成核作用,会高估粒子的吸湿性.随着上升速度增大,吸湿增长因子降低,降低程度与粒子初始高度的相对湿度有关.上升高度通过改变气块相对湿度的变化来影响气溶胶吸湿增长因子. 相似文献
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Effect of model errors in ambient air humidity on the aerosol optical depth obtained via aerosol hygroscopicity in eastern China in the Atmospheric Chemistry and Climate Model Intercomparison Project datasets 
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下载免费PDF全文 CHANG Wenyuan 《大气和海洋科学快报》2019,(3):162-169
当前全球气候模式普遍低估中国东部气溶胶光学厚度(AOD)。本文表明,模式低估中国东部地表大气相对湿度是AOD低估的原因之一。研究基于国际大气化学气候模式比较计划的干气溶胶质量浓度结果,用再分析湿度数据替换模拟湿度以计算AOD变化。结果表明,替换后我国大气相对湿度增加,多模式平均的华南年均AOD因此增长45%,华北6-8月AOD增长33%。不同模式采用相似的硫酸盐吸湿增长曲线。相对湿度低估对AOD模拟影响程度主要受吸湿颗粒质量浓度和相对湿度概率分布影响,该结论有助于解释我国AOD模拟误差。 相似文献
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通过对2004年秋冬季(9—12月)4次雾霾天气过程在京、津背景地区——北京上甸子大气本底污染监测站观测的大气气溶胶光学特性的分析,发现该地区气溶胶光学特性受天气过程的影响很大。4次雾霾影响时段,平均气溶胶散射系数σ_(sca)、吸收系数σ_(abs)和单次散射反照率ω都远高于雾霾过后清洁时段的数值,其中气溶胶ω在雾霾影响时段为0.94～0.97,雾霾后为0.84～0.86,平均减小了0.1左右,表明雾霾天气有利于气溶胶的累积和生成。相比于光吸收性气溶胶,雾霾天气对光散射性气溶胶的增加更为有利,反映了二次气溶胶的产生及其对消光的贡献可能有较大增加。 相似文献
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广州市大气能见度影响因子的贡献研究 总被引：25，自引：4，他引：21
通过对广州市2004年10月1日~11月5日污染性气体NO2、气溶胶散射系数和吸收系数以及粒子化学成分组成等观测资料的分析,得到了影响广州市大气能见度因子的贡献比例:大气气溶胶散射bsa为75.26%、大气气溶胶吸收baa为12.89%、水汽bsw为5.78%、气体吸收bag为3.68%、大气分子散射bsg为2.38%;给出了不同粒径段气溶胶对散射的贡献比例;然后采用逐步多元线性回归得到了大气干气溶胶散射系数与PM2.5、PM10及化学成分的经验关系式;并给出了广州市区气溶胶的质量散射系数。 相似文献
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基于相对湿度、能见度等气象数据,分析气溶胶吸湿增长特性,有助于了解气溶胶对大气环境和区域气候的影响。利用南京地区2016年1—12月、2017年2—12月、2018年1—8月和12月相对湿度和能见度等数据,通过非线性拟合研究气溶胶吸湿增长因子(f(RH))与相对湿度(RH)之间的关系。结果表明,吸湿增长因子在RH值较低(<80%)时,增长率较小;当RH值较高(>80%)时,增长率迅速增大。吸湿增长因子随着月RH值变化而表现出较大差异。此外,当南京地区盛行西风时,高能见度出现的时次较多。f(RH)与PM2.5/PM10成正比,PM2.5/PM10值越高,对应的气溶胶光学吸湿增长因子往往会越高。 相似文献
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中国大气气溶胶研究综述 总被引：108，自引：3，他引：108
文中综合论述了近 2 0年来中国大气气溶胶研究状况 ,包括对大气气溶胶的直接采样分析 ,地面和卫星的遥感 ,大气气溶胶辐射特性及其气候效应的研究以及沙尘暴的形成、输送及气候效应的研究等。直接采样分析不仅研究了气溶胶的浓度和粒子谱分布等特性 ,而且也对其化学组分做了分析 ,高空气球采样得到了对流层和低平流层的气溶胶样品 ,并用X能谱电子显微镜进行了分析。地面遥感和多种卫星资料 ,包括AVHRR ,SVISSR ,TOMS ,POLDER等 ,被用来研究大气气溶胶的辐射特性 ,并提出了用消光和前向散射相结合和利用天空散射光分布反演粒子谱分布相函数等方法。开展了有关气溶胶气候效应的数值模拟研究 ,并对非球形粒子以及吸湿性粒子的作用做了专门的计算。对沙尘粒子的直接观测为研究其生成条件和输送特性提供了基础数据。文中对不同的研究方法进行了初步评述 ,并对气溶胶的研究提出几点建议。 相似文献
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A humidification system was deployed to measure aerosol hygroscopicity at a rural site of the North China Plain during the haze red-alert period 17–22 December 2016. The aerosol scattering coefficients under dry [relative humidity (RH) < 30%] and wet (RH in the range of 40%–85%) conditions were simultaneously measured at wavelengths of 450, 550, and 700 nm. It is found that the aerosol scattering coefficient and backscattering coefficient increased by only 29% and 10%, respectively when RH went up from 40% to 80%, while the hemispheric backscatter fraction went down by 14%, implying that the aerosol hygroscopicity represented by the aerosol scattering enhancement factor f(RH) is relatively low and RH exerted little effects on the aerosol light scattering in this case. The scattering enhancement factors do not show significant differences at the three wavelengths, only with an approximate 2% variation, suggesting that the aerosol hygroscopicity is independent of the wavelength. Aerosol hygroscopicity is highly dependent on the aerosol chemical composition. When there is a large mass fraction of inorganics and a small mass fraction of organic matter, f(RH) reaches a high value. The fraction of NO3– was strongly correlated with the aerosol scattering coefficient at RH = 80%, which suggests that NO3– played an important role in aerosol hygroscopic growth during the heavy pollution period. 相似文献
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A Closure Study of Aerosol Hygroscopic Growth Factor during the 2006 Pearl River Delta Campaign 总被引：3，自引：0，他引：3
LIU Xingang ZHANG Yuanhang WEN Mengting WANG Jingli Jinsang JUNG CHANG Shih-yu HU Min ZENG Limin Young Joon KIM 《大气科学进展》2010,27(4):947-956
Measurements of aerosol physical, chemical and optical parameters
were carried out in Guangzhou, China from 1 July to 31 July 2006 during the
Pearl River Delta Campaign. The dry aerosol scattering coefficient was measured
using an integrating nephelometer and the aerosol scattering coefficient for
wet conditions was determined by subtracting the sum of the aerosol absorption
coefficient, gas scattering coefficient and gas absorption coefficient from the
atmospheric extinction coefficient. Following this, the aerosol hygroscopic
growth factor, f(RH), was calculated as the ratio of wet and dry aerosol
scattering coefficients. Measurements of size-resolved chemical composition,
relative humidity (RH), and published functional relationships between particle
chemical composition and water uptake were likewise used to find the aerosol
scattering coefficients in wet and dry conditions using Mie theory for
internally- or externally-mixed particle species [(NH4)2SO4, NH4NO3, NaCl, POM, EC and residue]. Closure was obtained by comparing
the measured f(RH) values from the nephelometer and other in situ optical
instruments with those computed from chemical composition and thermodynamics.
Results show that the model can represent the observed f(RH) and is
appropriate for use as a component in other higher-order models. 相似文献
13.
Assessment of the radiative forcing of aerosols in models still lacks sufficient input data for aerosol hygroscopicity. The light scattering enhancement factor [ f(RH, λ)] is a crucial parameter for describing aerosol hygroscopic growth properties.In this paper, we provide a survey of f(RH, λ) studies in China for the past seven years, including instrument developments of humidified nephelometers, ambient f(RH, λ) measurements in China, f(RH, λ) parameterization schemes, and f(RH, λ)applications in aerosol measurements. Comparisons of different f(RH, λ) parameterizations are carried out to check their performance in China using field measurement datasets. We also summary the parameterization schemes for predicting f(RH, λ)with aerosol chemical compositions. The recently developed methods to observe other aerosol properties using f(RH, λ)measurements, such as calculating the aerosol hygroscopicity parameter, cloud condensation nuclei number concentration,aerosol liquid water content, and aerosol asymmetry factor, are introduced. Suggestions for further research on f(RH, λ) in China are given. 相似文献
14.
Denghui JI Zhaoze DENG Xiaoyu SUN Liang RAN Xiangao XIA Disong FU Zijue SONG Pucai WANG Yunfei WU Ping TIAN Mengyu HUANG 《大气科学进展》2020,37(7):671-678
Aerosols in the atmosphere not only degrade visibility, but are also detrimental to human health and transportation. In order to develop a method to estimate PM_(2.5) mass concentration from the widely measured visibility, a field campaign was conducted in Southwest China in January 2019. Visibility, ambient relative humidity(RH), PM_(2.5) mass concentrations and scattering coefficients of dry particles were measured. During the campaign, two pollution episodes, i.e., from 4-9 January and from 10-16 January, were encountered. Each of the two episodes could be divided into two periods. High aerosol hygroscopicity was found during the first period, when RH was higher than 80% at most of the time, and sometimes even approached 100%. The second period experienced a relatively dry but more polluted condition and aerosol hygroscopicity was lower than that during the first period. An empirical relationship between PM_(2.5) mass concentration and visibility(ambient aerosol extinction) under different RH conditions could thus be established. Based on the empirical relationship,PM_(2.5) mass concentration could be well estimated from visibility and RH. This method will be useful for remote sensing of PM_(2.5) mass concentration. 相似文献
15.
H.-C. Hansson M. J. Rood S. Koloutsou-Vakakis K. Hämeri D. Orsini A. Wiedensohler 《Journal of Atmospheric Chemistry》1998,31(3):321-346
Organic compounds in the atmosphere can influence the activation, growth and lifetimes of haze, fog and cloud droplets by changing the condensation and evaporation rates of liquid water by these aqueous aerosol particles. Depending on the nature and properties of the organic compounds, the change can be to enhance or reduce these rates. In this paper we used a tandem differential mobility analyzer (TDMA) to examine the effect of tetracosane, octanoic acid, and lauric acid on the hygroscopic properties of NaCl aerosol particles at relative humidities (RH) between 30 and 95%. These organic compounds have been identified in ambient aerosol particle samples. A slight lowering of the deliquescence relative humidity (DRH) and suppression of hygroscopic growth for the NaCl-organic compound mixtures were observed when compared to pure NaCl particles. The growth of pure NaCl particles was 2.25 in diameter at 85% RH while the growth of the mixed particles was 1.3 to 1.7 in particle diameter at 85% RH with organic mass fraction of 30–50%. This shows that these organic compounds have to be present in rather large mass fractions to effect the hygroscopic behavior to a similar degree observed for ambient aerosol during field measurements. Despite the mixing of the organic material with NaCl, hysteresis was observed for decreasing RH histories, suggesting the formation of metastable droplets. These laboratory results are strikingly similar to ambient field results. For example, if the total organic mass fraction of the particles is between 0.30 and 0.50, the particle growth at 85% RH is about a factor of 1.4 for the laboratory and field measurements. Such reduction in growth compared to the pure inorganic salt is in contradiction to speculations concerning significant effects by organic compounds on cloud condensation nuclei and thus formation on clouds. 相似文献
16.
THE IMPACT OF RELATIVE HUMIDITY ON THE RADIATIVE PROPERTY AND RADIATIVE FORCING OF SULFATE AEROSOL* 下载免费PDF全文
下载免费PDF全文 With the data of complex refractive index of sulfate aerosol,the radiative properties of the aerosol under 8 relative humidity conditions are calculated in this paper.By using the concentration distribution from two CTM models and LASG GOALS/AGCM,the radiative forcing due to hygroscopic sulfate aerosol is simulated.The results show that:(1)With the increase of relative humidity,the mass extinction coefficiency factor decreases in the shortwave spectrum;single scattering albedo keeps unchanged except for a little increase in longwave spectrum,and asymmetry factor increases in whole spectrum.(2)Larger differences occur in radiative forcingsimulated by using two CTM data,and the global mean forcing is -0.268 and -0.816 W/m2,respectively.(3)When the impact of relative humidity on radiative property is taken into account,the distribution pattern of radiative forcing due to the wet particles is very similar to that of dry sulfate,but the forcing value decreases by 60%. 相似文献
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Dong Xia Ling Chen Huizhong Chen Xuyu Luo Tao Deng 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(4):341-352
The atmospheric aerosols can absorb moisture from the environment due to their hydrophilicity and thus affect atmospheric radiation fluxes. In this article, the ultraviolet radiation and relative humidity (RH) data from ground observations and a radiative transfer model were used to examine the influence of RH on ultraviolet radiation flux and aerosol direct radiative forcing under the clear-sky conditions. The results show that RH has a significant influence on ultraviolet radiation because of aerosol hygroscopicity. The relationship between attenuation rate and RH can be fitted logarithmically and all of the R2 of the 4 sets of samples are high, i.e. 0.87, 0.96, 0.9, and 0.9, respectively. When the RH is 60%, 70%, 80% and 90%, the mean aerosol direct radiative forcing in ultraviolet is ?4.22W m?2, ?4.5W m?2, ?4.82W m?2 and ?5.4W m?2, respectively. For the selected polluted air samples the growth factor for computing aerosol direct radiative forcing in the ultraviolet for the RH of 80% varies from 1.19 to 1.53, with an average of 1.31. 相似文献
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2009年上海浦东新区能见度资料的深度分析——兼论高时间分辨率地面观测资料的应用 总被引：2，自引：1，他引：1
利用2009年上海浦东新区气象站高时间分辨率的能见度资料及其同步地面气象要素资料,在气块静力稳定的假设下研究了由于辐射冷却引起的霾或雾在演变的各阶段气溶胶吸湿性增长及其消光系数随相对湿度的变化,结果表明：气溶胶吸湿性增长率f（RH）随相对湿度的增长具有先慢后快平滑连续的特点;气溶胶吸湿性增长率在不同季节有所差异,在夏季和秋季较高,在冬季和春季时较低;平均而言,当相对湿度从40%增大到95%时,气溶胶吸湿性增长率可达6.6;对比国内外实验和观测结果,发现f（RH）随相对湿度的变化曲线与硫酸铵亲水增长相似;在这种雾消散时,随着气温的升高,测量给出的相对湿度值不会立即下降,而是在接近饱和的情况下维持一段时间,然后再迅速下降,其滞后大约为1～2小时。这很可能是测湿元件不能及时反映外界湿度变化所致。 相似文献