المؤلفون: Wang, Haoji^1,2 (AUTHOR), Su, Yue^1,2 (AUTHOR) suyue@imu.edu.cn, Liu, Yangzheng^1,2 (AUTHOR), Xie, Fei^1,3 (AUTHOR), Zhou, Xingjun³ (AUTHOR), Yu, Ruihong¹ (AUTHOR), Lü, Changwei^1,2 (AUTHOR), He, Jiang^1,2 (AUTHOR) ndjhe@imu.edu.cn

المصدر: Journal of Environmental Sciences (Elsevier). Apr2024, Vol. 138, p74-87. 14p.

مصطلحات موضوعية: ATMOSPHERIC aerosols, CITIES & towns, OPTICAL properties, ABSORPTION coefficients, CHEMICAL properties

مستخلص: • Water-soluble brown carbon (BrC) in PM 2.5 was extracted in the resource-dependent cities. • The optical properties, chemical compositions and sources of BrC were characterized.ac • Humic-like and protein-like substances were the predominant according to EEM and PARAFAC. • WS-BrC revealed the difference of energy consumption in developing and developed regions. As a vital type of light-absorbing aerosol, brown carbon (BrC) presents inherent associations with atmospheric photochemistry and climate change. However, the understanding of the chemical and optical properties of BrC is limited, especially in some resource-dependent cities with long heating periods in northwest China. This study showed that the annual average abundances of Water-soluble BrC (WS-BrC) were 9.33±7.42 and 8.69±6.29 µg/m3 in Baotou and Wuhai and the concentrations, absorption coefficient (Abs 365), and mass absorption efficiency (MAE 365) of WS-BrC presented significant seasonal patterns, with high values in the heating season and low values in the non-heating season; while showing opposite seasonal trends for the Absorption Ångström exponent (AAE 300-400). Comparatively, the levels of WS-BrC in developing regions (such as cities in Asia) were higher than those in developed regions (such as cities in Europe and Australia), indicating the significant differences in energy consumption in these regions. By combining fluorescence excitation-emission matrix (EEM) spectra with the parallel factor (PARAFAC) model, humic-like (C1 and C2) and protein-like (C3) substances were identified, and accounted for 61.40%±4.66% and 38.6%±3.78% at Baotou, and 60.33%±6.29% and 39.67%±4.17% at Wuhai, respectively. The results of source apportionment suggested that the potential source regions of WS-BrC varied in heating vs. non-heating seasons and that the properties of WS-BrC significantly depended on primary emissions (e.g., combustion emissions) and secondary formation. [ABSTRACT FROM AUTHOR]

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المؤلفون: Riemer, Nicole¹ (AUTHOR) nriemer@illinois.edu, West, Matthew² (AUTHOR)

المصدر: Aerosol Science & Technology. Jul2024, Vol. 58 Issue 7, p721-726. 6p.

مصطلحات موضوعية: *AEROSOLS, *ATMOSPHERIC aerosols

مستخلص: Each particle of an atmospheric aerosol is composed of multiple chemical components, and a variety of particle compositions are present within a particle population. This fact poses unique challenges to modelers and experimentalists who strive to ultimately quantify the impact of aerosols on human health and on climate. This editorial lays out some fundamentals for how to think about the aerosol state and explores implications of the emergent aerosol property called aerosol mixing state. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

المؤلفون: Zhao, Zhijian¹ (AUTHOR) zhaozhijian@xyc.edu.cn, Tonooka, Hideyuki² (AUTHOR) hideyuki.tonooka.dr@vc.ibaraki.ac.jp

المصدر: Atmosphere. Jun2024, Vol. 15 Issue 6, p712. 25p.

مصطلحات موضوعية: *ATMOSPHERIC aerosols, *AEROSOL analysis, *SULFATE aerosols, *EVIDENCE gaps, *SPRING, *BLUE light

مستخلص: The Qinghai-Tibetan Plateau (QTP) is the largest permafrost-covered area in the world, and it is critical to understand accurately and dynamically the cyclical changes in atmospheric aerosols in the region. However, due to the scarcity of researchers in this field and the complexity of analyzing the spatial and temporal dynamics of aerosols, there is a gap in research in this area, which we hope to fill. In this study, we constructed a new fusion algorithm based on the V5.2 algorithm and the second-generation deep blue algorithm through the introduced weight factor of light and dark image elements. We used the algorithm to analyze the spatial and temporal changes in aerosols from 2009–2019. Seasonal changes and the spatial distribution of aerosol optical depth (AOD) were analyzed in comparison with the trend of weight factor, which proved the stability of the fusion algorithm. Spatially, the AOD values in the northeastern bare lands and southeastern woodland decreased most significantly, and combined with the seasonal pattern of change, the AOD values in this region were higher in the spring and fall. In these 11 years, the AOD values in the spring and fall decreased the most, and the aerosol in which the AOD decreases occurred should be the cooling-type sulfate aerosol. In order to verify the accuracy of the algorithm, we compared the AOD values obtained by the algorithm at different time intervals with the measured AOD values of several AERONET stations, in which the MAE, RMSE, and R between the AOD values obtained by the algorithm and the measured averages of the 12 nearest AERONET stations in the QTP area were 0.309, 0.094, and 0.910, respectively. In addition, this study also compares the AOD results obtained from the fusion algorithm when dynamically weighted and mean-weighted, and the results show that the error value is smaller in the dynamic weighting approach in this study. [ABSTRACT FROM AUTHOR]

المؤلفون: Yu, Chenjie¹ (AUTHOR) chenjie.yu@lisa.ipsl.fr, Pangui, Edouard² (AUTHOR), Tu, Kevin² (AUTHOR), Cazaunau, Mathieu² (AUTHOR), Feingesicht, Maxime² (AUTHOR), Xavier, Landsheere² (AUTHOR), Bourrianne, Thierry³ (AUTHOR), Michoud, Vincent¹ (AUTHOR), Cantrell, Christopher² (AUTHOR), Onasch, Timothy B.⁴ (AUTHOR), Freedman, Andrew⁴ (AUTHOR), Formenti, Paola¹ (AUTHOR) paola.formenti@lisa.ipsl.fr

المصدر: Atmospheric Measurement Techniques. 2024, Vol. 17 Issue 11, p3419-3437. 19p.

مصطلحات موضوعية: *ALBEDO, *ATMOSPHERIC aerosols, *ATMOSPHERIC chemistry, *LIGHT scattering, *SOLAR radiation, *ABSORPTION coefficients

مصطلحات جغرافية: PARIS (France)

مستخلص: Atmospheric aerosols impact the Earth's climate system directly by scattering and absorbing solar radiation, and it is important to characterise the aerosol optical properties in detail. This study reports the development and validation of an airborne dual-wavelength cavity-attenuated phase-shift (CAPS) single monitor, named A2S2 (Aerosol Absorption Spectral Sizer), based on the commercial CAPS single-scattering albedo monitor (CAPS-PM SSA ; Aerodyne), to simultaneously measure the aerosol optical scattering and extinction at both 450 and 630 nm wavelengths. Replaced pressure and temperature sensors and an additional flow control system were incorporated into the A2S2 for its utilisation on board research aircraft measuring within the troposphere. The evaluation of A2S2 characteristics was performed in the laboratory and included the investigation of the signal-to-noise ratio, validation of performance at various pressure levels, optical closure studies and intercomparing with the currently validated techniques. The chamber experiments show that the A2S2 can perform measurements at sample pressures as low as 550 hPa and at sample temperatures as high as 315 K. Based on the Allan analysis results, we have evaluated that the minimum detection limit of the measurements shows that the measurements have a limit accuracy of ∼ 2 Mm-1 at 450 nm and ∼ 1 Mm-1 at 630 nm for 1 Hz measurements of both scattering coefficients (σsca) and extinction coefficients (σext). The optical closure study with size-selected polystyrene latex (PSL) particles shows that the truncation error of the A2S2 is negligible for particles with particle volume diameter (Dp) < 200 nm, while, for the larger sub-micrometre particles, the measurement uncertainty of A2S2 increases but remains less than 20 %. The average factors to correct the truncation error are 1.13 and 1.05 for 450 and 630 nm, respectively. A simplified truncation correction, dependent on the scattering Ångström exponent (SAE), was developed to rectify truncation errors of the future A2S2 field measurement data. The σsca and σext measured by the A2S2 show good agreement with the concurrent measured results from the nephelometer and the CAPS particle extinction monitor (CAPS-PM ex). The absorption coefficient (σabs) derived through the extinction-minus-scattering (EMS) method by the A2S2 also corresponds with the results obtained from the aethalometer. The A2S2 was successfully deployed during an aircraft measurement campaign (Atmospheric ChemistRy Of the Suburban foreSt – ACROSS) conducted in the vicinity of Paris and the surrounding regions. The average SSA measured during the entire ACROSS flight campaign is 0.86 and 0.88 at 450 and 630 nm, respectively, suggesting that light-absorbing organic aerosols play a significant role. The average SAE and absorption Ångström exponent (AAE) varied due to measurements in various pollution conditions. The results presented in this study indicate that the A2S2 instrument is reliable for measuring aerosol σsca and σext at both blue and red wavelengths, and it stands as a viable substitute for future airborne evaluations of aerosol optical properties. [ABSTRACT FROM AUTHOR]

المؤلفون: Zhao, Chuanfeng^1,2 (AUTHOR) cfzhao@pku.edu.cn, Sun, Yue³ (AUTHOR), Yang, Jie³ (AUTHOR), Li, Jiefeng¹ (AUTHOR), Zhou, Yue³ (AUTHOR), Yang, Yikun¹ (AUTHOR), Fan, Hao⁴ (AUTHOR), Zhao, Xin³ (AUTHOR)

المصدر: Science Bulletin. May2024, Vol. 69 Issue 10, p1569-1580. 12p.

مصطلحات موضوعية: *AEROSOLS, *ATMOSPHERIC aerosols, *WATER vapor, *WIND speed, *ATMOSPHERIC models, *ATMOSPHERIC water vapor measurement, *RAIN-making

مستخلص: [Display omitted] Aerosols greatly influence precipitation characteristics, thereby impacting the regional climate and human life. As an indispensable factor for cloud formation and a critical radiation budget regulator, aerosols can affect precipitation intensity, frequency, geographical distribution, area, and time. However, discrepancies exist among current studies due to aerosol properties, precipitation types, the vertical location of aerosols and meteorological conditions. The development of technology has driven advances in current research, but understanding the aerosol effects on precipitation remain complex and challenging. This paper revolves around the following topics from the two perspectives of Aerosol-Radiation Interaction (ARI) and Aerosol-Cloud Interaction (ACI): (1) the influence of different vertical locations of absorbing/scattering aerosols on the atmospheric thermal structure; (2) the fundamental theories of ARI reducing surface wind speed, redistributing water vapour and energy, and then modulating precipitation intensity; (3) different aerosol types (absorbing versus scattering) and aerosol concentrations causing different precipitation diurnal and weekly variations; (4) microphysical processes (cloud water competition, invigoration effect, and evaporation cooling) and observational evidence of different effects of aerosols on precipitation intensity, including enhancing, inhibiting, and transitional effects from enhancement to suppression; and (5) how meteorology, water vapor and dynamics influencing the effect of ACI and ARI on precipitation. In addition, this review lists the existing issues and future research directions for attaining a more comprehensive understanding of aerosol effects on precipitation. Overall, this review advances our understanding of aerosol effects on precipitation and could guide the improvement of weather and climate models to predict complex aerosol-precipitation interactions more accurately. [ABSTRACT FROM AUTHOR]

المؤلفون: Xia, Junji¹ (AUTHOR) xiajunji@my.swjtu.edu.cn, Zhu, Fengrong^1,2 (AUTHOR) zhufr@swjtu.edu.cn, Zhao, Xingbing³ (AUTHOR), Liu, Jing¹ (AUTHOR), Liu, Hu¹ (AUTHOR), Yuan, Guotao¹ (AUTHOR), Sun, Qinning¹ (AUTHOR), Xie, Lei¹ (AUTHOR), Jin, Min¹ (AUTHOR), Chen, Long¹ (AUTHOR), Wang, Yang¹ (AUTHOR), Liu, Yu¹ (AUTHOR), Song, Tengfei⁴ (AUTHOR)

المصدر: Remote Sensing. May2024, Vol. 16 Issue 10, p1695. 15p.

مصطلحات موضوعية: *ATMOSPHERIC aerosols, *OPTICAL properties, *COSMIC rays, *AEROSOL analysis, *SPRING

مصطلحات جغرافية: TIBETAN Plateau, MYANMAR

مستخلص: The accuracy of cosmic ray observations by the Large High Altitude Air Shower Observatory Wide Field-of-View Cherenkov/Fluorescence Telescope Array (LHAASO-WFCTA) is influenced by variations in aerosols in the atmosphere. The solar photometer (CE318-T) is extensively utilized within the Aerosol Robotic Network as a highly precise and reliable instrument for aerosol measurements. With this CE318-T 23, 254 sets of valid data samples over 394 days from October 2020 to October 2022 at the LHAASO site were obtained. Data analysis revealed that the baseline Aerosol Optical Depth (AOD) and Ångström Exponent (AE) at 440–870 nm (AE440–870nm) of the aerosols were calculated to be 0.03 and 1.07, respectively, suggesting that the LHAASO site is among the most pristine regions on Earth. The seasonality of the mean AOD is in the order of spring > summer > autumn = winter. The monthly average maximum of AOD440nm occurred in April (0.11 ± 0.05) and the minimum was in December (0.03 ± 0.01). The monthly average of AE440–870nm exhibited slight variations. The seasonal characterization of aerosol types indicated that background aerosol predominated in autumn and winter, which is the optimal period for the absolute calibration of the WFCTA. Additionally, the diurnal daytime variations of AOD and AE across the four seasons are presented. Our analysis also indicates that the potential origins of aerosol over the LHAASO in four seasons were different and the atmospheric aerosols with higher AOD probably originate mainly from Northern Myanmar and Northeast India regions. These results are presented for the first time, providing a detailed analysis of aerosol seasonality and origins, which have not been thoroughly documented before in this region, also enriching the valuable materials on aerosol observation in the Hengduan Mountains and Tibetan Plateau. [ABSTRACT FROM AUTHOR]

المؤلفون: DeLand, Matthew T.¹ (AUTHOR) matthew.deland@ssaihq.com, Kowalewski, Matthew G.² (AUTHOR) matthew.g.kowalewski@nasa.gov, Colarco, Peter R.² (AUTHOR) peter.r.colarco@nasa.gov, Ramos-Izquierdo, Luis² (AUTHOR) luis.a.ramos-izquierdo@nasa.gov

المصدر: Remote Sensing. May2024, Vol. 16 Issue 9, p1531. 11p.

مصطلحات موضوعية: *STRATOSPHERIC aerosols, *ATMOSPHERIC aerosols, *FORCE & energy, *AEROSOLS, *ORBITS (Astronomy), *ENERGY budget (Geophysics)

مستخلص: Atmospheric aerosols represent an important component of the Earth's climate system because they can contribute both positive and negative forcing to the energy budget. We are developing the Aerosol Radiometer for Global Observations of the Stratosphere (ARGOS) instrument to provide improved measurements of stratospheric aerosols in a compact package. ARGOS makes limb scattering measurements from space in eight directions simultaneously, using two near-IR wavelengths for each viewing direction. The combination of forward and backward scattering views along the orbit track gives additional information to constrain the aerosol phase function and size distribution. Cross-track views provide expanded spatial coverage. ARGOS will have a demonstration flight through a hosted payload provider in the fall of 2024. The instrument has completed pre-launch environmental testing and radiometric characterization tests. The hosted payload approach offers advantages in size, weight, and power margins for instrument design compared to other approaches, with significant benefits in terms of reducing infrastructure requirements for the instrument team. [ABSTRACT FROM AUTHOR]

المؤلفون: Chang, Liang¹ (AUTHOR), Li, Jing^1,2 (AUTHOR) jing-li@pku.edu.cn, Ren, Jingjing³ (AUTHOR), Xiong, Changrui¹ (AUTHOR), Zhang, Lu^4,5 (AUTHOR)

المصدر: Atmospheric Measurement Techniques. 2024, Vol. 17 Issue 9, p2637-2648. 12p.

مصطلحات موضوعية: *ATMOSPHERIC aerosols, *AEROSOLS, *LOGNORMAL distribution, *ALGORITHMS, *LIDAR, *LOTKA-Volterra equations

مستخلص: The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite has been widely used in climate and environment studies to obtain the vertical profiles of atmospheric aerosols. To retrieve the vertical profile of aerosol extinction, the CALIOP algorithm assumes column-averaged lidar ratios based on a clustering of aerosol optical properties measured at surface stations. On one hand, these lidar ratio assumptions may not be appropriate or representative at certain locations. One the other hand, the two-wavelength design of CALIOP has the potential to constrain aerosol size information, which has not been considered in the operational algorithm. In this study, we present a modified inversion algorithm to simultaneously retrieve aerosol extinction and effective radius profiles using two-wavelength elastic lidars such as CALIOP. Specifically, a lookup table is built to relate the lidar ratio with the Ångström exponent calculated using aerosol extinction at the two wavelengths, and the lidar ratio is then determined iteratively without a priori assumptions. The retrieved two-wavelength extinction at each layer is then converted to the particle effective radius assuming a lognormal distribution. The algorithm is tested on synthetic data, Raman lidar measurements and then finally the real CALIOP backscatter measurements. Results show improvements over the CALIPSO operational algorithm by comparing with ground-based Raman lidar profiles. [ABSTRACT FROM AUTHOR]

المؤلفون: Virtanen, Timo H.¹ (AUTHOR) timo.h.virtanen@fmi.fi, Sundström, Anu-Maija² (AUTHOR) anu-maija.sundstrom@fmi.fi, Suhonen, Elli² (AUTHOR) elli.suhonen@fmi.fi, Lipponen, Antti¹ (AUTHOR) antti.lipponen@fmi.fi, Arola, Antti¹ (AUTHOR) antti.arola@fmi.fi, O'Dell, Christopher³ (AUTHOR) christopher.odell@colostate.edu, Nelson, Robert R.⁴ (AUTHOR) robert.r.nelson@jpl.nasa.gov, Lindqvist, Hannakaisa² (AUTHOR) hannakaisa.lindqvist@fmi.fi

المصدر: Atmospheric Measurement Techniques Discussions. 4/29/2024, p1-40. 40p.

مصطلحات موضوعية: *ATMOSPHERIC aerosols, *SOLAR radiation, *AEROSOLS, *CARBON dioxide, *CITIES & towns, *ATMOSPHERIC acoustics

مستخلص: Satellite-based observations of carbon dioxide (CO2) are sensitive to all processes that affect the propagation of radiation in the atmosphere, including scattering and absorption by atmospheric aerosols. Therefore, accurate retrievals of column-averaged CO2 (XCO2) benefit from detailed information on the aerosol conditions. This is particularly relevant for future missions focusing on observing anthropogenic CO2 emissions, such as the Copernicus Anthropogenic CO2 Monitoring mission (CO2M). To fully prepare for CO2M observations, it is informative to investigate existing observations in addition to other approaches. Our focus here is on observations from the NASA Orbiting Carbon Observatory -2 (OCO-2) mission. In the operational full-physics XCO2 retrieval used to generate OCO-2 level 2 products, the aerosol properties are known to have high uncertainty but their main objective is to facilitate CO2 retrievals. We evaluate the OCO-2 product from the point of view of aerosols by comparing the OCO-2 retrieved aerosol properties to collocated Moderate Resolution Imaging Spectro-radiometer (MODIS) Aqua Dark Target aerosol products. We find that there is a systematic difference between the aerosol optical depth (AOD, τ) values retrieved by the two instruments, such that τOCO−2 ∼ 0.4τMODIS. We also find a dependence of the XCO2 on the AOD difference, indicating an aerosol-induced effect in the XCO2 retrieval. In addition, we find a weak but statistically significant correlation between MODIS AOD and XCO2, which can be partly explained by natural covariance and co-emission of aerosols and CO2 but is partly masked by the aerosol-induced XCO2 bias. Furthermore, we find that issues in the OCO-2 aerosol retrieval may lead to misclassification of the quality flag for a small fraction of OCO-2 retrievals. Based on MODIS data, 4.1 % of low AOD cases are incorrectly classified as high AOD (low quality) pixels, while 16.5 % of high AOD cases are erroneously classified as low AOD (high quality) pixels. Finally, we investigate the effect of an AOD threshold on the fraction of acceptable XCO2 data. We find that relaxing the MODIS AOD threshold from 0.2 to 0.5 (at 550 nm), which is the goal for the CO2M, increases the fraction of acceptable data by 14 percentage points globally, and by 31 percentage points for urban areas. [ABSTRACT FROM AUTHOR]

المؤلفون: Zhang, Wenhao^1,2 (AUTHOR) zhangwh@radi.ac.cn, Liu, Sijia^1,2 (AUTHOR) liusijia1007@stumail.nciae.edu.cn, Chen, Xiaoyang^1,2 (AUTHOR) chenxiaoyang0926@stumail.nciae.edu.cn, Mi, Xiaofei³ (AUTHOR) mixf@aircas.ac.cn, Gu, Xingfa^1,3 (AUTHOR) guxf@aircas.ac.cn, Yu, Tao^1,3 (AUTHOR) yutao@radi.ac.cn

المصدر: Remote Sensing. Apr2024, Vol. 16 Issue 8, p1410. 23p.

مصطلحات موضوعية: *AIR quality, *ATMOSPHERIC aerosols, *AEROSOLS, *STANDARD deviations, *DATA quality, *ENVIRONMENTAL sciences

مستخلص: Atmospheric aerosols affect climate change, air quality, and human health. The aerosol optical depth (AOD) is a widely utilized parameter for estimating the concentration of atmospheric aerosols. Consequently, continuous AOD monitoring is crucial for environmental studies. However, a method to continuously monitor the AOD throughout the day or night remains a challenge. This study introduces a method for estimating the All-Day AOD using ground air quality and meteorological data. This method allows for the hourly estimation of the AOD throughout the day in the Beijing–Tianjin–Hebei (BTH) region and addresses the lack of high temporal resolution monitoring of the AOD during the nighttime. The results of the proposed All-Day AOD estimation method were validated against AOD measurements from Advanced Himawari Imager (AHI) and Aerosol Robotic Network (AERONET). The R2 between the estimated AOD and AHI was 0.855, with a root mean square error of 0.134. Two AERONET sites in BTH were selected for analysis. The results indicated that the absolute error between the estimated AOD and AERONET was within acceptable limits. The estimated AOD showed spatial and temporal trends comparable to those of AERONET and AHI. In addition, the hourly mean AOD was analyzed for each city in BTH. The hourly mean AOD in each city exhibits a smooth change at night. In conclusion, the proposed AOD estimation method offers valuable data for investigating the impact of aerosol radiative forcing and assessing its influence on climate change. [ABSTRACT FROM AUTHOR]