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Automated Detection of the Planetary Boundary Layer Height and Cloud in Qingdao Based on Morphological Processing

IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2023年 16卷 5951-5962页

作者： Chen, Yehui Jin, Xiaomei Weng, Ningquan Zhu, Wenyue Liu, Qing Liu, Nana Chinese Acad Sci Anhui Inst Opt Key Lab Atmospher Opt Fine MechHFIPS Hefei Peoples R China Univ Sci Technol China Sci Isl Branch Grad Sch Hefei 230026 Peoples R China Adv Laser Technol Lab Anhui Prov Hefei 230037 Peoples R China Univ Sci Technol China Sch Environm Sci & Optoelect Technol Hefei 230026 Peoples R China

Clouds have double functions for lidar: Noise and useful information. In this study, the clouds were separated from temporal-spatial coherent Doppler wind lidar with a high temporal resolution image based on the morphological open filter, which produced a filtered image and a cloud image. First, the wavelet covariance transform was employed for the filtered image to retrieve planetary boundary layer height (PBLH) including surface layer height and mixed layer height. Then, the Savitzky-Golay filter with different time-window widths was applied for temporally multiscale analysis of PBLH's features,which related to temperature and humidity. Last, the areas of cloud image were estimated and related to specification rain water content in clouds. The results show that the proposed method is effective and stable for automatic detection of PBLH and cloud using only a single lidar, which was verified by the data of Qingdao in China.

关键词： Clouds Laser radar aerosols Signal to noise ratio Meteorology Atmospheric measurements Wavelet transforms Coherent Doppler wind lidar (CDWL) morphological opening filter Index Terms planetary boundary layer (PBL) specification rain water content (SRWC) wavelet covariance transform (WCT)

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Synthesis of Metal Oxide Nanoparticles in Flame Sprays: Review on Process Technology, Modeling, and Diagnostics

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ENERGY & FUELS 2021年第7期35卷 5495-5537页

作者： Meierhofer, Florian Fritsching, Udo Leibniz Inst Mat Engn IWT D-28359 Bremen Germany Univ Bremen Fac Prod Engn D-28359 Bremen Germany Univ Bremen MAPEX Ctr Mat & Proc D-28359 Bremen Germany Braunschweig Univ Technol Inst Semicond Technol IHT D-38106 Braunschweig Germany Braunschweig Univ Technol Lab Emerging Nanometrol LENA D-38106 Braunschweig Germany

The gas synthesis of nanoparticles has gained major interest by different industries and research groups for the development of new materials and their subsequent implementation in numerous devices and applications. Actually, there are numerous research and application activities in flame-based nanoparticle production, mainly focusing on the process and its development, the in situ and ex situ analyses in experiments and simulations and new material and material combination developments. This review provides an overview on the flame synthesis of metal oxide nanoparticles and focuses in particular on the process design of flame spray pyrolysis (FSP). The first part of this review describes the historical background of flame-based particle production and further summarizes the emerging developments, achievements, and trends during the past 2 decades. The second part covers a general process overview of the flame aerosol-based manufacturing by explaining the key aspects of synthesis (chemical raw materials, metal precursors, solvents, and reactor configurations), in situ conditioning approaches, and powder and byproduct collection, along with additional post-processing steps (storage, handling, and modification). Applications of flame-made nanoparticles involve catalysts, gas sensors, energy storage materials, and nanotoxicity studies, among others, which will not be discussed in detail but are overviewed by listing the latest reviews of the respective field. The third part focuses on the growth mechanisms of solid particle products in liquid droplet/spray pyrolysis (liquid-to-particle and gas-to-particle conversion). The concept of characteristic process times is then exemplified for a lab-scaled FSP reactor, while afterward, particle dynamics and continuum models for reactor simulation are reviewed. The fourth part is a survey of more than 20 different diagnostic techniques that are commonly employed for characterization of reactive sprays and flame-made powders. We

关键词： Nanomaterials Oxides Metals Precursors Nanoparticles aerosols Metal oxide nanoparticles Chemical engineering and industrial chemistry

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ANALYSIS OF THE SPATIAL-DISTRIBUTION OF AEROSOL DISPERSIONS

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ANNALS OF NUCLEAR ENERGY 1995年第1期22卷 17-28页

作者： GIMENEZ, M SCHLAMP, M CLAUSSE, A Nuclear Safety Division Centro Atómico Bariloche 8400 S. C. de Bariloche Argentina

The dispersion of contaminant particles in a fluid media is studied considering the main mechanisms for coagulation and removal, with special emphasis on its application to the held of nuclear reactor safety. Starting from the general balance equation for the aerosol size spectrum as a function of position and time, a diffusion-convection equation is derived using the method of moments. The equation is analyzed for a variety of cases, and the solutions are discussed and compared with existing codes calculations as well as exact analytical solutions. The method presented is very useful in the sense that it reduces the complexity of the spatial aerosol dispersion to the domain of the classical diffusion-convection transport analysis.

关键词： aerosols

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Analysis of wind vertical component characteristics in the stratosphere

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RUSSIAN METEOROLOGY AND HYDROLOGY 2009年第11期34卷 724-731页

作者： Beresnev, S. A. Gryazin, V. I. Gribanov, K. G. Ural State Univ Ekaterinburg 620083 Russia

Height, time, and latitude dependences are analyzed of zonal mean vertical component of wind velocity for the period of 1992-2006 from the UKMO atmospheric general circulation model. It is shown that the ascending wind speed can provide vertical transport, against gravity, of rather large (up to 3-5 mu m) aerosol particles with density to 1.0-1.5 g/cm(3) in the stratosphere and mesosphere. The wind velocity vertical component is supposedly a significant factor of particle motion up to 30-40-km levels and can affect sedimentation rate and residence time of the aerosol particles in the stratosphere. Structure of the mean vertical component of wind velocity allows occurrence of dynamically stable aerosol layers in the middle stratosphere.

关键词： aerosols

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Real-world emission factors of fine and ultrafine aerosol particles for different traffic situations in Switzerland

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ENVIRONMENTAL SCIENCE & TECHNOLOGY 2005年第21期39卷 8341-8350页

作者： Imhof, D Weingartner, E Ordóñez, C Gehrigt, R Hill, N Buchmann, B Baltensperger, U Paul Scherrer Inst Lab Atmospher Chem CH-5232 Villigen Switzerland EMPA Lab Air Pollut Environm Technol CH-8600 Dubendorf Switzerland

Extended field measurements of particle number (size distribution of particle diameters, D, in the range between 18 nm and 10 mu m), surface area concentrations, and PM1 and PM10 mass concentrations were performed in Switzerland to determine traffic emissions using a comprehensive set of instruments. Measurements took place at roads with representative traffic regimes: at the kerbside of a motorway (120 km h(-1)), a highway (80100 km h-1), and in an urban area with stop-and-go traffic (0-50 km h(-1)) regulated by light signals. Mean diurnal variations showed that the highest pollutant concentrations were during the morning rush hours, especially of the number density in the nanoparticle size range (D < 50 nm). From the differences between up- and downwind concentrations (or differences between kerbside and background concentrations for the urban site), "real-life" emission factors were derived using NO, concentrations to calculate dilution factors. Particle number and volume emission factors of different size ranges (18-50 nm, 18100 nm, and 18-300 nm) were derived for the total vehicle fleet and separated into a light-duty (LDV) and a heavy-duty vehicle (HDV) contribution. The total particle number emissions per vehicle were found to be about 11.7-13.5 X 10(14) particles km(-1) for constant speed (80-120 km h(-1)) and 3.9 x 10(14) particles km-1 for urban driving conditions. LDVs showed higher emission factors at constant high speed than under urban disturbed traffic flow. In contrast, HDVs emitted more air pollutants during deceleration and acceleration processes in stop-and-go traffic than with constant speed of about 80 km h(-1). On average, one HDV emits a 10-30 times higher amount of particulate air pollutants (in terms of both number and volume) than one LDV.

关键词： Diurnal variations Particulate air pollutants Atmospheric pollution Aerosol particles Environmental sciences Urban atmospheric pollution Particulate matter in urban air Nanoparticles Atmospheric pollution by motor vehicles Particle size aerosols Particulates Flow rates Air pollution traffic driving ability Emissions Automotive exhaust emissions Highways Wind Urban areas surface area

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What is the Role of Sea Surface Temperature in Modulating Cloud and Precipitation Properties over the Southern Ocean?

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JOURNAL OF CLIMATE 2016年第20期29卷 7453-7476页

作者： Huang, Yi Siems, Steven T. Manton, Michael J. Rosenfeld, Daniel Marchand, Roger McFarquhar, Greg M. Protat, Alain Monash Univ Sch Earth Atmosphere & Environm Melbourne Vic Australia Monash Univ Australian Res Council Ctr Excellence Climate Sys Melbourne Vic Australia Hebrew Univ Jerusalem Inst Earth Sci Jerusalem Israel Univ Washington Dept Atmospher Sci Seattle WA 98195 USA Univ Illinois Dept Atmospher Sci Urbana IL USA Australian Bur Meteorol Melbourne Vic Australia

This study employs four years of spatiotemporally collocated A-Train satellite observations to investigate cloud and precipitation characteristics in relation to the underlying properties of the Southern Ocean (SO). Results show that liquid-phase cloud properties strongly correlate with the sea surface temperature (SST). In summer, ubiquitous supercooled liquid water (SLW) is observed over SSTs less than about 4 degrees C. Cloud-top temperature (CTT) and effective radius of liquid-phase clouds generally decrease for colder SSTs, whereas the opposite trend is observed for cloud-top height, cloud optical thickness, and liquid water path. The deduced cloud depth is larger over the colder oceans. Notable differences are observed between "precipitating" and "nonprecipitating" clouds and between different ocean sectors. Using a novel joint SST-CTT histogram, two distinct liquid-phase cloud types are identified, where the retrieved particle size appears to increase with decreasing CTT over warmer water (SSTs> similar to 7 degrees C), while the opposite is true over colder water. Acomparison with the Northern Hemisphere (NH) storm-track regions suggests that the ubiquitous SLW with markedly smaller droplet size is a unique feature for the cold SO (occurring where SSTs< similar to 4 degrees C), while the presence of this cloud type is much less frequent over the NH counterparts, where the SSTs are rarely colder than about 4 degrees C at any time of the year. This study also suggests that precipitation, which has a profound influence on cloud properties, remains poorly observed over the SO with the current spaceborne sensors. Large uncertainties in precipitation properties are associated with the ubiquitous boundary layer clouds within the lowest kilometer of the atmosphere.

关键词： Clouds aerosols Air-sea interaction Cloud microphysics Cloud retrieval Satellite observations

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Complexity of Measuring and Representing the Hygroscopicity of Mixed Component Aerosol

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JOURNAL OF PHYSICAL CHEMISTRY A 2019年第8期123卷 1648-1660页

作者： Marsh, Aleksandra Rovelli, Grazia Miles, Rachael E. H. Reid, Jonathan P. Univ Bristol Sch Chem Bristol BS8 1TS Avon England

The validation of approaches to predict the hygroscopicity of complex mixtures of organic components in aerosol is important for understanding the hygroscopic response of organic aerosol in the atmosphere. We report new measurements of the hygroscopicity of mixtures of dicarboxylic acids and amino acids using a comparative kinetic electrodynamic balance (CK-EDB) approach, inferring the equilibrium water content of the aerosol from close to a saturation relative humidity (100%) down to 80%. We show that the solution densities and refractive indices of the mixtures can be estimated with an accuracy of better than +/- 2% using the molar refractive index mixing rule and densities and refractive indices for the individual binary organic-aqueous solutions. Further, we show that the often-used mass-, volume-, and mole-weighted mixing rules to estimate the hygroscopicity parameter kappa can overestimate the hygroscopic parameter by a factor of as much as 3, highlighting the need to understand the specific nonideal interactions that may arise synergistically in mixtures and cannot be represented by simple models. Indeed, in some extreme cases the hygroscopicity of a multicomponent mixture can be very close to that for the least hygroscopic component. For mixtures of similar components for which no additional synergistic interactions need be considered, the hygroscopicity of the mixed component aerosol can be estimated with high accuracy from the hygroscopic response of the binary aqueous-organic aerosol. In conclusion, we suggest that the hygroscopicity of multicomponent organic aerosol can be highly nonadditive and that simple correlations of hygroscopicity with composition may often misrepresent the level of complexity essential to interpreting aerosol hygroscopicity.

关键词： Solution chemistry Peptides and proteins Monomers Mixtures aerosols

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Role of pH in Aerosol Processes and Measurement Challenges

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JOURNAL OF PHYSICAL CHEMISTRY A 2019年第7期123卷 1275-1284页

作者： Freedman, Miriam Arak Ott, Emily-Jean E. Marak, Katherine E. Penn State Univ Dept Chem University Pk PA 16802 USA

pH is one of the most basic chemical properties of aqueous solution, but its measurement in nanoscale aerosol particles presents many challenges. The pH of aerosol particles is of growing interest in the atmospheric chemistry community because of its demonstrated effects on heterogeneous chemistry and human health, as well as potential effects on climate. The authors have shown that phase transitions of aerosol particles are sensitive to pH, focusing on systems that undergo liquid-liquid phase separation. Currently, aerosol pH is calculated indirectly from knowledge of species present in the gas and aerosol phases through the use of thermodynamic models. From these models, ambient aerosol is expected to be highly acidic (pH similar to 0-3). Direct measurements have focused on model systems due to the difficulty of this measurement. This area is one in which physical chemists should be encouraged to contribute because of the potential consequences for aerosol processes in the environment.

关键词： Anions Nanoparticles aerosols pH Phase transitions

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Condensational particle growth device for reliable cell exposure at the air-liquid interface to nanoparticles

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AEROSOL SCIENCE AND TECHNOLOGY 2019年第12期53卷 1415-1428页

作者： Tilly, Trevor B. Ward, Ryan X. Luthra, Jiva K. Robinson, Sarah E. Eiguren-Fernandez, Arantzazu Lewis, Gregory S. Salisbury, Richard L. Lednicky, John A. Sabo-Attwood, Tara L. Hussain, Saber M. Wu, Chang-Yu Univ Florida Engn Sch Sustainable Infrastruct & Environm Dept Environm Engn Sci Gainesville FL USA US Air Force Res Lab 711th Human Performance Wing RHDJ Mol Mech BranchBioeffects DivAirman Syst Direct Dayton OH USA Univ Florida Dept Environm & Global Hlth Gainesville FL USA Aerosol Dynam Inc Berkeley CA USA

A first-of-its-kind aerosol exposure device for toxicity testing, referred to as the Dosimetric Aerosol in Vitro Inhalation Device (DAVID), was evaluated for its ability to deliver airborne nanoparticles to lung cells grown as air-liquid interface (ALI) cultures. For inhalation studies, ALI lung cell cultures exposed to airborne nanoparticles have more relevancy than the same cells exposed in submerged culture because ALI culture better represents the respiratory physiology and consequently more closely reflect cellular response to aerosol exposure. In DAVID, water condensation grows particles as small as 5 nm to droplets sized >5 mu m for inertial deposition at low flow rates. The application of DAVID for nanotoxicity analysis was evaluated by measuring the amount and variability in the deposition of uranine nanoparticles and then assessing the viability of ALI cell cultures exposed to clean-air under the same operational conditions. The results showed a low coefficient of variation, <0.25, at most conditions, and low variability in deposition between the exposure wells, trials, and operational flow rates. At an operational flow rate of 4 LPM (liter per minute), no significant changes in cell viability were observed, and minimal effects observed at 6 LPM. The reliable and gentle deposition mechanism of DAVID makes it advantageous for nanoparticle exposure. Copyright (c) 2019 American Association for Aerosol Research

关键词： aerosols

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Dusty Atmospheric Rivers: Characteristics and Origins

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JOURNAL OF CLIMATE 2020年第22期33卷 9749-9762页

作者： Voss, Kara K. Evan, Amato T. Prather, Kimbery A. Ralph, F. Martin Univ Calif San Diego Scripps Inst Oceanog La Jolla CA 92093 USA Univ Calif San Diego Scripps Inst Oceanog Dept Chem & Biochem La Jolla CA 92093 USA Univ Calif San Diego Scripps Inst Oceanog Ctr Western Weather & Water Extremes La Jolla CA 92093 USA

Atmospheric rivers (AR) are narrow bands of strong horizontal transport of water vapor in the midlatitudes that can cause extreme precipitation, which contributes to beneficial water supply and sometimes flooding. The precipitation productivity of an AR is affected by microphysical processes, including the influence of aerosols. Earlier case studies have shown that some ARs over the North Pacific Ocean contain dust from Africa and Asia that can strongly influence precipitation by acting as ice nuclei. This paper explores how commonly dust and ARs occur together, or in close proximity. A "dust score'' is introduced to characterize the dustiness of the environment associated with ARs by using satellite-based observations. This method is applied to days on which one or more ARs made landfall along the west coast of the United States between 2001 and 2018. The dust score is used to describe the seasonality and year-to-year variability of dusty-environment ARs. Dusty ARs occur primarily in the early spring (March-April), and dust is preferentially found within the warm sector of AR-associated extratropical cyclones and is also enhanced in the cold sector. Year-to-year variability in dust score is dependent more on year-to-year variability in dust than on the frequency of AR days. This year-to-year variability is also strongly related to correlations between the frequency of ARs and the dustiness of the northeastern Pacific, motivating additional investigation into potential dynamical association between dust and ARs.

关键词： Atmosphere Extratropical cyclones aerosols Satellite observations Seasonal cycle

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