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沙尘气溶胶辐射强迫全球分布的模拟研究 总被引：7，自引：2，他引：5
为了定景了解沙尘气溶胶对气候的影响,文中利用一个改进的辐射传输模式,结合伞球气溶胶数据集(G-ADS),计算了晴空条件下,冬夏两季沙尘气溶胶的直接辐射强迫在对流层顶和地面的全球分布,并讨论了云对沙尘气溶胶辐射强迫的影响.计算结果表明,对北半球冬季和夏季而言,在对流层顶沙尘气溶胶的全球短波辐射强迫的平均值分别为-0.477和-0.501 W/m2;长波辐射强迫分别为0.11和0.085 W/m2;全球平均短波地面辐射强迫冬夏两季分别为-1.362和-1.559 W/m2;长波辐射强迫分别为0.274和0.23 W/m2.沙尘气溶胶在对流层顶和地面的负辐射强迫的绝对值郁随太阳天顶角的余弦和地表反照率的增加而增大;地表反照率对沙尘气溶胶辐射强迫的强度和分布都有重要影响.研究指出:云对沙尘气溶胶的直接辐射强迫的影响不仅取决于云量,而且取决于云的高度和云水路径,以及地面反照率和太阳高度角等综合因素.中云和低云对沙尘气溶胶在对流层顶的短波辐射强迫的影响比高云明显.云的存在都使对流层顶长波辐射强迫减少,其中低云的影响最为明显.因此,在估算沙尘气溶胶总的直接辐射强迫时,云的贡献不可忽视. 相似文献
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刘新春 《沙漠与绿洲气象(新疆气象)》2014,8(3):68-74
沙尘气溶胶对全球气候变化的影响是当前国内外研究的热点问题。我国学者对沙尘气溶胶也开展了广泛的研究,尤其是在近10年,科研工作者对沙尘气溶胶的物理化学特性及其对气候的影响进行了重点研究。本文主要对沙尘气溶胶的物理特性（浓度、粒径谱分布、垂直分布特征及光学特性）、化学特性以及气候效应等方面的研究进行了综述,并对今后沙尘气溶胶研究中所面临的科学问题进行了展望。 相似文献
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基于国际大气化学-气候模式比较计划模式数据评估中国沙尘气溶胶直接辐射强迫 总被引：2，自引：0，他引：2
目前气候模式对沙尘气溶胶直接辐射强迫模拟仍有很大不确定性,多模式对比有助于定量评估不确定范围。国际大气化学—气候模式比较计划（Atmospheric Chemistry and Climate Model Intercomparison Project,ACCMIP）旨在评估当前模式对短寿命大气成分辐射强迫和气候效应的模拟能力。基于7个ACCMIP模式模拟的中国地区沙尘气溶胶浓度,我们评估了中国区域沙尘气溶胶直接辐射强迫和不确定性范围。结果显示,中国区域沙尘气溶胶年排放总量为215±163 Tg a-1,区域年均地表浓度为41±27 μg m-3,柱浓度为9±4 kg m-2,光学厚度为0.09±0.05。中国区域年均沙尘气溶胶产生的大气顶短波、长波和总辐射强迫分别为-1.3±0.8 W m-2、0.7±0.4 W m-2和-0.5±0.7 W m-2;地表短波、长波和总的辐射强迫值为-1.5±1.0 W m-2、1.8±0.9 W m-2和0.2±0.2 W m-2。沙尘气溶胶长波辐射强迫对沙尘浓度的垂直分布敏感。高层沙尘气溶胶浓度越大,其在大气顶产生更强的正值长波辐射强迫。然而,沙尘气溶胶短波辐射强迫主要受整层沙尘柱浓度控制,对沙尘浓度的垂直分布较不敏感。本文结果可为中国沙尘气溶胶的气候模拟提供参考。 相似文献
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沙尘气溶胶对气候的影响效应是目前全球气候变化研究的热点之一.在简单综述近10 a我国西北地区科研人员在沙尘源区的研究、起沙机制、沙尘气溶胶的光、化学特性和辐射气候效应等方面科研成果的基础上,对今后沙尘气溶胶研究中所面临的一些科学问题进行了展望. 相似文献
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中国地区春季沙尘气溶胶短波辐射气候效应数值模拟研究 总被引：1，自引：0，他引：1
利用耦合了起沙模型(MEDM)的区域气候模式RegCM3,模拟研究了2000年春季中国地区沙尘气溶胶短波辐射气候效应。结果表明,春季中国沙尘气溶胶垂直负荷的大值区主要位于南疆盆地和阿拉善高原。引入沙尘气溶胶后,中国地区地表均出现负的辐射强迫,地面气温普遍降低,中低层(400 hPa层以下)大气温度则呈上升趋势。沙尘源区及其下游地区总云量及降水主要呈减少趋势,云量与降水的分布特征与空中流场的变化趋势一致性较好。 相似文献
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浑善达克沙地沙尘气溶胶的粒谱特征 总被引：22，自引：2，他引：20
浑善达克沙地是我国主要沙尘气溶胶源地之一,但对其沙尘气溶胶特征一直缺乏研究.2001年4月末到5月初,在内蒙古浑善达克沙地利用PMS Fssp-100型激光粒谱仪进行了大气气溶胶的外场观测,取得了晴天、扬沙和沙尘暴天气条件下沙尘粒子的数浓度采样资料,通过统计分析研究,总结出浑善达克沙地在不同天气条件下近地面沙尘气溶胶的粒谱分布规律.所得统计结果表明了与其他源地沙尘气溶胶的共同点、差异之处及其原因.这一结果也为沙尘气溶胶辐射气候效应的数值模拟提供了新的实测依据. 相似文献
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ＳＯ２构成的去凝结核会增加行星反照率，因此可使行星变冷。这种效应可抵消由温室气体增加造成的全球增暖。在二维模式中详细论述了矿物燃料燃烧与影响云反照率的ＳＯ２的关系以便计算气候效应。尽管我们在硫酸盐气溶胶和大气源汇方面的知识存在很大缺陷，还是有可能得出一般性结论。按保守算法，结果表明由于ＳＯ２排放导致的变冷作用目前能抵消ＣＯ２增温效应的５０％，模式预测出自１９８０年以来有一个强大的增温趋势，仅１９８ 相似文献
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局地云量变化气候效应的数值模拟 总被引：3，自引：3，他引：3
本文用统计得到的东半球夏季平均云量资料，利用改进的云－辐射计算模式，在三维有限区域模式中模拟局地云量变化的气候效应。模拟结果表明，高原地区和热带辐合带云量变化造成的气候效应都主要表现在青藏高原地区。在低反照率时，高原地区云量减少使该地区地表加热，引起高低空气压系统加强；高反照率时结果相反。热带辐合带云量减少会引起青藏高原地区降温和气压系统减弱。 相似文献
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使用RegCM3-dust区域气候模式,单向嵌套MIROC3．2-hires全球模式输出结果,在IPCCA1B温室气体排放情景下,对中国及东亚地区进行了当代（1991年-2000年）和未来（2091年-2100年）水平分辨率为50km的气候以及沙尘气溶胶数值模拟试验。结果表明,模式对中国地区地面气温、降水和东亚沙尘气溶胶空间分布模拟较好。未来东亚沙尘气溶胶年平均起沙通量增加2％,其中12月-3月由于地表积雪量的减少而增加,4月-11月由于10m风速的减小而减少,不同强度的强起沙事件同样12月-3月增加,4月-11月减少。年平均沙尘气溶胶柱含量增加14％,其中3月-5月和8月略减少,其它月份增加。沙尘气溶胶引起地面（SRF）负辐射强迫和沙尘源区大气顶（TOA）正辐射强迫、下游地区TOA负辐射强迫,受沙尘气溶胶辐射强迫的影响,地面起沙通量和柱含量减少。 相似文献
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Estimation of the Aerosol Radiative Effect over the Tibetan Plateau Based on the Latest CALIPSO Product 总被引：2，自引：0，他引：2
Based on the CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation) Version 4.10 products released on 8 November 2016, the Level 2 (L2) aerosol product over the Tibetan Plateau (TP) is evaluated and the aerosol radiative effect is also estimated in this study. As there are still some missing aerosol data points in the daytime CALIPSO Version 4.10 L2 product, this study re-calculated the aerosol extinction coefficient to explore the aerosol radiative effect over the TP based on the CALIPSO Level 1 (L1) and CloudSat 2B-CLDCLASS-LIDAR products. The energy budget estimation obtained by using the AODs (aerosol optical depths) from calculated aerosol extinction coefficient as an input to a radiative transfer model shows better agreement with the Earth’s Radiant Energy System (CERES) and CloudSat 2B-FLXHR-LIDAR observations than that with the input of AODs from aerosol extinction coefficient from CALIPSO Version 4.10 L2 product. The radiative effect and heating rate of aerosols over the TP are further simulated by using the calculated aerosol extinction coefficient. The dust aerosols may heat the atmosphere by retaining the energy in the layer. The instantaneous heating rate can be as high as 5.5 K day–1 depending on the density of the dust layers. Overall, the dust aerosols significantly affect the radiative energy budget and thermodynamic structure of the air over the TP, mainly by altering the shortwave radiation budget. The significant influence of dust aerosols over the TP on the radiation budget may have important implications for investigating the atmospheric circulation and future regional and global climate. 相似文献
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Identification of Aerosol Types and Their Optical Properties in the North China Plain Based on Long-Term AERONET Data 
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下载免费PDF全文 SUN Li XIA Xiang-Ao WANG Pu-Cai CHEN Hong-Bin Philippe GOLOUB ZHANG Wen-Xing 《大气和海洋科学快报》2013,(4):216-222
Characterization of aerosols is required to reduce uncertainties in satellite retrievals of global aerosols and for modeling the effects of these aerosols on climate.Aerosols in the North China Plain(NCP) are complex,which provides a good opportunity to study key aerosol optical properties for various aerosol types.A cluster analysis of key optical properties obtained from Aerosol Robotic Network(AERONET) data in Beijing and Xianghe during 2001-11 was performed to identify dominant aerosol types and their associated optical properties.Five dominant aerosol types were identified.The results show that the urban/industrial aerosol of moderate absorption was dominant in the region and that this type varied little with season.Urban/industrial aerosol of weak absorption was the next most common type and mainly occurs in summer,followed by that strong aerosols occurring mainly in winter.All were predominantly fine mode particles.Mineral dust(MD) and polluted dust(PD) occurred mainly in spring,followed by winter,and their absorption decreased with wavelength.In addition,aerosol dynamics and optical parameters such as refractive index and asymmetry factor were examined.Results show that the size of coarse mode particles decreased with AOD indicating the domination of external mixing between aerosols. 相似文献
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基于2007—2021年CALIPSO和MODIS主、被动卫星遥感探测数据,对塔克拉玛干沙漠和撒哈拉沙漠的气溶胶光学特性时空分布特征进行探究及对比分析。结果表明：（1）两大沙漠的沙尘气溶胶对总气溶胶的贡献率最大,气溶胶类型季节变化的相对单一性反映了塔克拉玛干沙漠和撒哈拉沙漠地区存在沙漠沙尘排放对总气溶胶成分的显著影响;（2）塔克拉玛干沙漠气溶胶光学厚度AOD的峰值出现在春季（春季>夏季>秋季>冬季）,而撒哈拉沙漠AOD的峰值出现在夏季（夏季>春季>秋季>冬季）;（3）撒哈拉沙漠总气溶胶抬升高度与塔克拉玛干沙漠相近,但近地面层消光系数明显小于塔克拉玛干沙漠;塔克拉玛干沙漠的消光系数平均值在所有季节中均大于撒哈拉沙漠,故塔克拉玛干沙漠的沙尘气溶胶AOD比撒哈拉沙漠的大;相比沙漠沙尘气溶胶,塔克拉玛干沙漠和撒哈拉沙漠都无明显的污染沙尘和抬升烟活动。上述研究结果揭示了两大沙漠源区沙尘气溶胶光学特性的观测事实与利用大气气溶胶时空变化特征反映区域气候变化的可能性。 相似文献
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Vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai 下载免费PDF全文
下载免费PDF全文 A comparative study on the vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai was conducted based on the data obtained from a micro pulse lidar.There was a distinct difference in layer thickness and extinction coefficient under the two types of weather conditions.Aerosols were concentrated below 1 km and the aerosol extinction coefficients ranged from 0.25 to 1.50km-1 on haze days.In contrast,aerosols with smaller extinction coefficients(0.20 0.35 km-1) accumulated mainly from the surface to 2 km on floating dust days.The seasonal variations of extinction and aerosol optical depth（AOD） for both haze and floating dust cases were similar greatest in winter,smaller in spring,and smallest in autumn.More than 85%of the aerosols appeared in the atmosphere below 1 km during severe haze and floating dust weather.The diurnal variation of the extinction coefficient of haze exhibited a bimodal shape with two peaks in the morning or at noon,and at nightfall,respectively.The aerosol extinction coefficient gradually increased throughout the day during floating dust weather.Case studies showed that haze aerosols were generated from the surface and then lifted up,but floating dust aerosols were transported vertically from higher altitude to the surface.The AOD during floating dust weather was higher than that during haze.The boundary layer was more stable during haze than during floating dust weather. 相似文献
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There are many indicators that human activity may change climate conditions all around the globe through emissions of greenhouse
gases. In addition, aerosol particles are emitted from various natural and anthropogenic sources. One important source of
aerosols arises from biomass burning, particularly in low latitudes where shifting cultivation and land degradation lead to
enhanced aerosol burden. In this study the counteracting effects of greenhouse gases and aerosols on African climate are compared
using climate model experiments with fully interactive aerosols from different sources. The consideration of aerosol emissions
induces a remarkable decrease in short-wave solar irradiation near the surface, especially in winter and autumn in tropical
West Africa and the Congo Basin where biomass burning is mainly prevailing. This directly leads to a modification of the surface
energy budget with reduced sensible heat fluxes. As a consequence, temperature decreases, compensating the strong warming
signal due to enhanced trace gas concentrations. While precipitation in tropical Africa is less sensitive to the greenhouse
warming, it tends to decrease, if the effect of aerosols from biomass burning is taken into account. This is partly due to
the local impact of enhanced aerosol burden and partly to modifications of the large-scale monsoon circulation in the lower
troposphere, usually lagging behind the season with maximum aerosol emissions. In the model equilibrium experiments, the greenhouse
gas impact on temperature stands out from internal variability at various time scales from daily to decadaland the same holds
for precipitation under the additional aerosol forcing. Greenhouse gases and aerosols exhibit an opposite effect on daily
temperature extremes, resulting in an compensation of the individual responses under the combined forcing. In terms of precipitation,
daily extreme events tend to be reduced under aerosol forcing, particularly over the tropical Atlantic and the Congo basin.
These results suggest that the simulation of the multiple aerosol effects from anthropogenic sources represents an important
factor in tropical climate change, hence, requiring more attention in climate modelling attempts. 相似文献
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Atmospheric aerosols influence the earth's radiative balance directly through scattering and absorbing solar radiation, and indirectly through affecting cloud properties. An understanding of aerosol optical properties is fundamental to studies of aerosol effects on climate. Although many such studies have been undertaken, large uncertainties in describing aerosol optical characteristics remain, especially regarding the absorption properties of different aerosols. Aerosol radiative effects are considered as either positive or negative perturbations to the radiation balance, and they include direct, indirect (albedo effect and cloud lifetime effect), and semi-direct effects. The total direct effect of anthropogenic aerosols is negative (cooling), although some components may contribute a positive effect (warming). Both the albedo effect and cloud lifetime effect cool the atmosphere by increasing cloud optical depth and cloud cover, respectively. Absorbing aerosols, such as carbonaceous aerosols and dust, exert a positive forcing at the top of atmosphere and a negative forcing at the surface, and they can directly warm the atmosphere. Internally mixed black carbon aerosols produce a stronger warming effect than externally mixed black carbon particles do. The semi-direct effect of absorbing aerosols could amplify this warming effect. Based on observational (ground-and satellite-based) and simulation studies, this paper reviews current progress in research regarding the optical properties and radiative effects of aerosols and also discusses several important issues to be addressed in future studies. 相似文献
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The authors used a high-resolution regional climate model(RegCM3) coupled with a chemistry/aerosol module to simulate East Asian climate in 2006 and to test the climatic impacts of aerosols on regionalscale climate.The direct radiative forcing and climatic effects of aerosols(dust,sulfate,black carbon,and organic carbon) were discussed.The results indicated that aerosols generally produced negative radiative forcing at the top-of-the-atmosphere(TOA) over most areas of East Asia.The radiative forcing induced by aerosols exhibited significant seasonal and regional variations,with the strongest forcing occurring in summer.The aerosol feedbacks on surface air temperature and precipitation were clear.Surface cooling dominated features over the East Asian continental areas,which varied in the approximate range of-0.5 to-2°C with the maximum up to-3-C in summer over the deserts of West China.The aerosols induced complicated variations of precipitation.Except in summer,the rainfall generally varied in the range of-1 to 1 mm d-1 over most areas of China. 相似文献
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大气气溶胶研究的前沿问题 总被引：60，自引：3，他引：57
从4个方面对大气气溶胶研究的前沿问题作了总结和分析：气溶胶的基本特征、气溶胶的气候效应、沙尘气溶胶以及气溶胶对健康环境的影响。介绍了当前国际上有关的大气气溶胶研究计划,讨论了未来大气气溶胶研究的主要领域及研究方向。 相似文献