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Competing Atmospheric and Surface-Driven Impacts of Absorbing aerosols on the East Asian Summertime Climate

JOURNAL OF CLIMATE 2017年第22期30卷 8929-8949页

作者： Persad, Geeta G. Paynter, David J. Ming, Yi Ramaswamy, V. Carnegie Inst Sci Stanford CA 20005 USA NOAA Geophys Fluid Dynam Lab Princeton NJ USA

East Asia has some of the largest concentrations of absorbing aerosols globally, and these, along with the region's scattering aerosols, have both reduced the amount of solar radiation reaching Earth's surface regionally (solar dimming) and increased shortwave absorption within the atmosphere, particularly during the peak months of the East Asian summer monsoon (EASM). This study analyzes how atmospheric absorption and surface solar dimming compete in driving the response of regional summertime climate to anthropogenic aerosols, which dominates, and why-issues of particular importance for predicting how East Asian climate will respond to projected changes in absorbing and scattering aerosol emissions in the future. These questions are probed in a state-of-the-art general circulation model using a combination of realistic and novel idealized aerosol perturbations that allow analysis of the relative influence of absorbing aerosols' atmospheric and surface-driven impacts on regional circulation and climate. Results show that even purely absorption-driven dimming decreases EASM precipitation by cooling the land surface, counteracting climatological land-sea contrast and reducing ascending atmospheric motion and onshore winds, despite the associated positive top-of-the-atmosphere regional radiative forcing. Absorption-driven atmospheric heating does partially offset the precipitation and surface evaporation reduction from surface dimming, but the overall response to aerosol absorption more closely resembles the response to its surface dimming than to its atmospheric heating. These findings provide a novel decomposition of absorbing aerosol's impacts on regional climate and demonstrate that the response cannot be expected to follow the sign of absorption's top-of-the-atmosphere or even atmospheric radiative perturbation.

关键词： Asia Atmosphere-land interaction Monsoons aerosols Climate models

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Impact of Atmospheric Flow Conditions on Fine aerosols in Sydney, Australia

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AEROSOL AND AIR QUALITY RESEARCH 2017年第7期17卷 1746-1759页

作者： Crawford, Jagoda Cohen, David D. Griffiths, Alan D. Chambers, Scott D. Williams, Alastair G. Stelcer, Eduard Australian Nucl Sci & Technol Org Locked Bag 2001 Kirrawee Dc NSW 2232 Australia

We apply a simple objective measure of an airshed's degree of ventilation and determine the impact on PM2.5 observations at Lucas Heights, Sydney, Australia. We extend the analysis of previous studies, which considered total PM2.5, by: using positive matrix factorisation to split the aerosol mass by source type;and using Radon-222 measurements as an independent indicator of ventilation and mixing. For this coastal airshed we found that for 64% of the time, conditions could be classified into four categories: local recirculation ( LRC;15%), stagnation (19.5%), regional recirculation (RRC;10.9%), or ventilation (18.6%). Mean PM2.5 concentrations under recirculation (in this study separated into;LRC and RRC) were 33% higher than under stagnation and can be double that of concentrations under ventilation. Since the combination of LRC and RRC events account for around 26% of all events, recirculation effects on PM2.5 concentrations are significant. However, we found that airshed ventilation doesn't affect PM2.5 concentrations from all sources evenly. Considering the three main sources of total PM2.5 at this site (vehicle exhaust 26.3%, secondary sulfate 23.7% and aged industrial sulfur 20.6%), conditions leading to the highest concentrations differ. The highest vehicle exhaust concentrations occur under LRC, the highest aged-industrial-sulphur concentrations occur under RRC, and secondary sulfur had similarly high concentrations under LRC and RRC. Under LRC the concentration from vehicle exhaust can be up to a factor of 3.9 greater than under ventilation. On a seasonal basis, RRC flow is most likely to occur in summer and spring (the warmer months of the year when sea breezes are more likely), whereas LRC conditions are more likely to occur in autumn and winter. These findings support those of previous studies, indicating that re-circulation can have a significant effect on PM2.5 concentrations in coastal airsheds, and the degree of impact can vary by source type.

关键词： aerosols Circulation Stagnation Positive Matrix Factorisation Ventilation

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Secondary sulphate aerosols and cirrus clouds detection with SEVIRI during Nabro volcano eruption

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2017年第20期38卷 5657-5672页

作者： Sellitto, Pasquale Seze, Genevieve Legras, Bernard UPMC Univ Paris 6 Lab Meteorol Dynam Ecole Normale Super PSL Res UnivEcole PolytechUniv Paris SaclaySor Paris France

Secondary sulphate aerosols (SSAs) and cirrus clouds in the upper troposphere-lower stratosphere (UTLS) are two key atmospheric constituents that canmodulate the Earth's radiative balance. In this article, we present a new preliminary detection algorithm for UTLS SSAs with the Spinning Enhanced Visible and Infrared Imager (SEVIRI) geostationary instrument. This algorithm is used in combination with a wellestablished existing clouds classification algorithm, to provide, in perspective, a combined tool to better characterize the aerosol-cirrus interactions at the regional scale and at very high temporal resolution, thus potentially contributing to the understanding of the SSAs' directindirect impact on the Earth's radiative balance. This new combined tool is tested on the Nabro volcano eruption of June-July 2011, which is known to have emitted a great amount of SSA gaseous precursors in the UTLS and to have interacted with the peculiar Asian monsoon dynamics during summer 2011. Although volcanic aerosol-cirrus interactions are not analysed in details at this stage, this work demonstrates that this can be carried out with SEVIRI by introducing a new dedicated SSA product. First results of the new SSA detection algorithm are encouraging towards the use of this combined product.

关键词： aerosols Temporal resolution Summer Ozone Monsoons Cirrus clouds Clouds Volcanoes Infrared instruments Stratosphere Sulfates Troposphere Volcanic activity Algorithms Earth atmosphere Volcanic eruptions Volcanic aerosols Mathematical models Interactions Dynamics Earth Detection

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Effect of aerosols on Ocean Parameters in India by Using Satellite Data

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Procedia Computer Science 2018年 132卷 1857-1865页

作者： S.N. Palve P.D. Nemade S.D. Ghude DYPIT Pimpri University of Pune“ India 411018 S.B. PatilCollege of Engineering. Indapur Pune 411018 India IITM“ Pune 411038 India

The rapid industrial and economic development in India leads to high level of pollution in environment. Due to increased level of aerosols oceans are warming. This paper highlights on aerosols effect on sea surface wind and sea surface temperature by using remote sensing data. The windplays important role in Aerosol Optical Depth (AOD) and radiative forcing and is analyzed using National Centers for Environmental Prediction (NCEP) monthly wind data. The radiative forcing observed is much higher and up to 60% of total AOD during summer monsoon. SeaSurface Temperature (SST) is another important parameter in ocean atmosphere system and a key variable in coupling the atmosphere and ocean. The SST has changed during the change of atmospheric pattern and it plays an important role in aerosols mechanism. The study observed that during summer monsoon SST over the South Eastern Tropical Indian Ocean (SETIO) much higher than Western Tropical Indian Ocean (WTIO) and it plays important role in aerosols mechanism.

关键词： aerosols MODIS SST Climate Change Atmosphere

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Dual polarization lidar for remote sensing of aerosols and clouds in the atmosphere

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CURRENT SCIENCE 2017年第6期113卷 1134-1138页

作者： Patel, Ajay Kumar Yellapragada, Bhavani Kumar Vishnu, R. Murti, M. V. R. Samuel, James Jebaseelan Indian Inst Technol Ctr Studies Resources Engn Bombay 400076 Maharashtra India Govt India Dept Space Natl Atmospher Res Lab Gadanki 517112 India VIT Univ Photon Nucl & Med Phys Div Vellore 632014 Tamil Nadu India

We describe an indigenously developed dual polarization lidar (DPL) system for remote sensing of the rangeresolved properties of non-spherical nature of airborne and cloud particles. The DPL system probes the atmosphere using a linearly polarized second harmonic Nd : YAG laser. The design of receiver optics is such that it separates the collected backscattered light into parallel and perpendicular polarization components. The ratio of intensity of perpendicular to parallel signals is known as the depolarization ratio (DR), which is a gauge for non-spherical particle content in the atmosphere. The DPL employs an external irradiance standard to calibrate the depolarization measurements. Comparison of simultaneous measurements between DPL and a similar instrument validates the utility of the system for cloud and aerosol studies. The altitude profiles of DR derived from lidar signals potentially indicate the type of major particle layers in the atmosphere.

关键词： aerosols clouds laser polarization lidar remote sensing

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Studies on the Climate Effects of Black Carbon aerosols in China and Their Sensitivity to Particle Size and Optical Parameters

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ADVANCES IN METEOROLOGY 2018年第Pt.3期2018卷 9341026-1-9341026-16页

作者： Ma, Xingxing Liu, Hongnian Wang, Xueyuan Peng, Zhen Nanjing Univ Sch Atmospher Sci Nanjing 210023 Jiangsu Peoples R China

In this paper, based on the principle of Mie scattering, we calculated the optical parameters of BC aerosols at different scales and then applied the new optical parameters to simulate the BC aerosols concentration distribution, radiative forcing, and their climate effects. We also compared the results of optical parameters of BC aerosols with homogeneous scales and analyzed the effect on climate. Compared with the conventional uniform-scheme optical parameterization, the concentrations of the first mode of BC aerosols simulated with the optical parameters that were recalculated based on the particle size are significantly higher, while the concentrations of the other modes and the total of BC aerosols are lower. In the respective of statistics, the changes of column burdens of BC in four modes are 0.085, -0.095, -0.089, -0.054 mg/m(2). The clear-sky TRF of BC are weakened in the value of 0.03 W/m(2) averaged over the domain, while the all-sky TRF of BC are enhanced of 0.06 W/m(2) in general. The warming effect of BC becomes weaker when using the new scheme by -0.04 K to -0.24 K. When using the new optical parameters scheme, the regional average surface concentrations of BC in four modes are 0.372, 0.264, 0.055 and 0.004 mu g/m(3), respectively. Especially, the first and the second mode account for as large as 53% and 38%. The surface concentration and column burden of total BC are 0.69 mu g/m(3) and 0.28 mg/m(2) can be dropped. The regional average direct RFs of BC at the top of the atmosphere are 0.49 W/m(2) under clear-sky and 0.36 W/m(2) under all-sky averaged over the domain. Over most areas of central China, North China, and East China, BC may increase the temperature in a range of 0.05 similar to 0.15 K, while over South China, BC shows cooling effect. In average, the precipitation variations caused by BC over East China, North China, South China, and Northeast China are -0.83, -0.05, -0.11, and -0.13 mm/d, respectively. As a whole, the variations of circulat

关键词： Studies Climate Black climate effects black Particle Size optical aerosols BC Climate

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Post-Monsoon Season Precipitation Reduction over South Asia: Impacts of Anthropogenic aerosols and Irrigation

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ATMOSPHERE 2018年第8期9卷 311-311页

作者： Chen, Wei-Ting Huang, Kung-Tzu Lo, Min-Hui LinHo, L. H. Natl Taiwan Univ Dept Atmospher Sci Taipei 10617 Taiwan

A significant declining trend of post-monsoon season precipitation in South Asia is observed between 2000-2014. Two major anthropogenic climate change drivers, aerosols and irrigation, have been steadily increasing during this period. The impacts of their regional and seasonal forcings on the post-monsoon precipitation reduction is investigated in this study through using idealized global climate simulations. The increased post-monsoon aerosol loadings lead to surface cooling downwind of the source areas by reduced surface shortwave flux. The addition of post-monsoon irrigation induces a stronger temperature decrease mainly around the irrigation hotspots by enhanced evaporation. Precipitation over West and North India is reduced post-monsoon by either aerosol or irrigation, which is mainly contributed by the anomalous subsidence. With concurrent forcings, the surface cooling and precipitation decrease are stronger and more extended spatially than the response to the separate forcing, with nonlinear amplification in surface cooling, but nonlinear damping in precipitation reduction. The anomalous vertical motion accelerates the transition of the regional meridional circulation, and hence the earlier withdrawal of the summer monsoon, which is consistent with the observed signals. The current results highlight the importance of including anthropogenic aerosol and irrigation effects in present and future climate simulations over South Asia.

关键词： post-monsoon precipitation drought aerosols irrigation South Asia CESM

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The comparative in vitro assessment of e-cigarette and cigarette smoke aerosols using the γH2AX assay and applied dose measurements

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TOXICOLOGY LETTERS 2017年 265卷 170-178页

作者： Thorne, David Larard, Sophie Baxter, Andrew Meredith, Clive Gaca, Marianna British Amer Tobacco R&D Ctr Southampton SO15 8TL Hants England

DNA damage can be caused by a variety of external and internal factors and together with cellular responses, can establish genomic instability through multiple pathways. DNA damage therefore, is considered to play an important role in the aetiology and early stages of carcinogenesis. The DNA-damage inducing potential of tobacco smoke aerosols in vitro has been extensively investigated;however, the ability of e-cigarette aerosols to induce DNA damage has not been extensively investigated. E-cigarette use has grown globally in recent years and the health implications of long term e-cigarette use are still unclear. Therefore, this study has assessed the induction of double-strand DNA damage in vitro using human lung epithelial cells to e-cigarette aerosols from two different product variants (a "cigalike" and a closed "modular" system) and cigarette smoke. A Vitrocell (R) VC 10 aerosol exposure system was used to generate and dilute cigarette smoke and e-cigarette aerosols, which were delivered to human bronchial epithelial cells (BEAS-2Bs) housed at the air-liquid-interface (ALI) for up to 120 min exposure (diluting airflow, 0.25-1 L/min). Following exposure, cells were immediately fixed, incubated with primary (0.1% gamma H2AX antibody in PBS) and secondary antibodies (DyLight (TM) 549 conjugated goat anti-mouse IgG) containing Hoechst dye DNA staining solution (0.2% secondary antibody and 0.01% Hoechst in PBS), and finally screened using the Cellomics Arrayscan VTI platform. The results from this study demonstrate a clear DNA damage-induced dose response with increasing smoke concentrations up to cytotoxic levels. In contrast, e-cigarette aerosols from two product variants did not induce DNA damage at equivalent to or greater than doses of cigarette smoke aerosol. In this study dosimetry approaches were used to contextualize exposure, define exposure conditions and facilitate comparisons between cigarette smoke and e-cigarette aerosols. Quartz crystal microbalance (

关键词： Dosimetry Cigarette smoke E-cigarette aerosols gamma-H2AX In vitro

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The South Asian Monsoon Response to Remote aerosols: Global and Regional Mechanisms

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2018年第20期123卷 11585-11601页

作者： Shawki, D. Voulgarakis, A. Chakraborty, A. Kasoar, M. Srinivasan, J. Imperial Coll London Dept Phys London England Imperial Coll London Grantham Inst Climate Change & Environm London England Ctr Atmospher & Ocean Sci IISc Bangalore Karnataka India Divecha Ctr Climate Change Bangalore Karnataka India

The South Asian summer monsoon has been suggested to be influenced by atmospheric aerosols, and this influence can be the result of either local or remote emissions. We have used the Hadley Centre Global Environment Model Version 3 (HadGEM3) coupled atmosphere-ocean climate model to investigate for the first time the centennial-scale South Asian precipitation response to emissions of sulfur dioxide (SO2), the dominant anthropogenic precursor of sulfate aerosol, from different midlatitude regions. Despite the localized nature of the regional heating that results from removing SO2 emissions, all experiments featured a similar large-scale precipitation response over South Asia, driven by ocean-modulated changes in the net cross-equatorial heat transport and an opposing cross-equatorial northward moisture transport. The effects are linearly additive, with the sum of the responses from the experiments where SO2 is removed from the United States, Europe, and East Asia resembling the response seen in the experiment where emissions are removed from the northern midlatitudes as a whole, but with East Asia being the largest contributor, even per unit of emission or top-of-atmosphere radiative forcing. This stems from the fact that East Asian emissions can more easily influence regional land-sea thermal contrasts and sea level pressure differences that drive the monsoon circulation, compared to emissions from more remote regions. Our results suggest that radiative effects of remote pollution should not be neglected when examining changes in South Asian climate and that and it is important to examine such effects in coupled ocean-atmosphere modeling frameworks. Plain Language Summary Atmospheric aerosols have been shown to exert a strong influence on global and regional climate through their radiative effects. The South Asian summer monsoon, a climate phenomenon on which billions of lives depend, has been suggested to be influenced by aerosols, and this influence can be the res

关键词： aerosols monsoon circulation intertropical convergence zone land‐sea thermal contrast

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Seasonal Variations in High Arctic Free Tropospheric aerosols Over Ny-Alesund, Svalbard, Observed by Ground-Based Lidar

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2018年第21期123卷 12353-12367页

作者： Shibata, T. Shiraishi, K. Shiobara, M. Iwasaki, S. Takano, T. Nagoya Univ Grad Sch Environm Studies Nagoya Aichi Japan Fukuoka Univ Dept Earth Syst Sci Fukuoka Fukuoka Japan Natl Inst Polar Res Tokyo Japan Natl Def Acad Japan Yokosuka Kanagawa Japan Chiba Univ Grad Sch Engn Chiba Japan

Free tropospheric aerosols over the high Arctic were observed by lidar for about 4 years from March 2014 at Ny-Alesund (78.9 degrees N, 11.9 degrees E). Vertical profiles of aerosol backscattering coefficients at two wavelengths, 532 and 1,064 nm, and depolarization ratio at one wavelength, 532 nm, are derived from these observations. The aerosol backscattering coefficient, the particle depolarization ratio, and the color ratio (the ratio of the backscattering coefficients at the two wavelengths) are roughly proportional to mass concentration, nonsphericity, and size of the aerosol particles, respectively. The aerosol backscattering coefficients indicate that monthly averaged concentration of aerosols was largest in the lowest free troposphere at about 1 km in altitude and was an order of magnitude less at an about 10 km in altitude and that the concentration of aerosols was highest from late spring to summer and lowest from late summer to fall. The depolarization ratio was less than a few percent in the troposphere during the four observed years. The depolarization ratio and the color ratio were greatest from winter to spring and smallest from summer to fall. The maxima in the monthly averaged nonsphericity and size precede the maxima in the monthly averaged concentration by a few months, indicating a seasonal change in the morphology or the characteristics of the aerosol particles. The small particle depolarization ratio of less than a few percent is consistent with previous findings that Arctic free tropospheric aerosol particles in spring are composed of a mixture of liquid phase sulfate and soot particles.

关键词： aerosols free troposphere high Arctic lidar seasonal variations

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