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parameterization of below-cloud scavenging for polydisperse fine mode aerosols as a function of rain intensity

Journal of Environmental Sciences 2023年第10期132卷 43-55页

作者： Chang Hoon Jung Hyung-Min Lee Dasom Park Young Jun Yoon Yongjoo Choi Junshik Um Seoung Soo Lee Ji Yi Lee Yong Pyo Kim Department of Health Management Kyungin Women’s UniversityIncheon 21041Korea Department of Environmental Science and Engineering Ewha Woman’s UniversitySeoulKorea Department of Environmental Engineering Konkuk UniversitySeoulKorea Korea Polar Research Institute IncheonKorea Department of Environment Hankuk University of Foreign StudiesYonginKorea Department of Atmospheric Sciences Pusan National UniversityBusanKorea Earth System Science Interdisciplinary Center University of MarylandCollege ParkMDUSA Research Center for Climate Sciences Pusan National UniversityBusanKorea Department of Chemical Engineering and Materials Science Ewha Womans UniversitySeoulKorea

The below-cloud aerosol scavenging process by precipitation is one of the most important mechanisms to remove aerosols from the atmosphere.Due to its complexity and dependence on both aerosol and raindrop sizes,wet scavenging process has been poorly treated,especially during the removal of fine particles.This makes the numerical simulation of below-cloud scavenging in large-scale aerosolmodels unrealistic.To consider the slip effects of submicron particles,a simplified expression for the diffusion scavenging was developed by approximating the Cunningham slip correction factor.The derived analytic solution was parameterized as a simple power function of rain intensity under the assumption of the lognormal size distribution of particles.The resultant approximated expression was compared to the observed data and the results of previous studies including a 3D atmospheric chemical transport model simulation.Compared with the default GEOS-Chem coefficient of 0.00106R0.61 and the observation-based coefficient of 0.0144R0.9268,the coefficient of a and b in∧m=aRb spread in the range of 0.0002-0.1959 for a and 0.3261-0.525 for b over a size distribution of GSD of 1.3–2.5 and a geometric mean diameter of 0.01-2.5μm.Overall,this study showed that the scavenging coefficient varies widely by orders of magnitude according to the size distribution of particles and rain intensity.This study also demonstrated that the obtained simplified expression could consider the theoretical approach of aerosol polydispersity.Our proposed analytic approach showed that results can be effectively applied for reduced computational burden in atmospheric modeling.

关键词： Below-cloud scavenging Polydisperse aerosol parameterization Cunningham correction factor Scavenging coefficient

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Improved Simulation of Summer Heavy Rainfall over Beijing and Henan by the YHGSM with Updated Subgrid Orographic Parameters

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Journal of Meteorological Research 2024年第3期38卷 504-529页

作者： Yingjie WANG Jianping WU Kaijun REN College of Computer Science and Technology National University of Defense Technology College of Meteorology and Oceanography National University of Defense Technology

In numerical weather prediction(NWP), the parameterization of orographic drag plays an important role in representing subgrid orographic effects. The subgrid orographic parameters are the key input to the parameterization of orographic drag. Currently, the subgrid orographic parameters in most NWP models were produced based on elevation datasets generated many years ago, with a coarse resolution and low quality. In this paper, using the latest high-quality elevation data and considering the applicable scale range of the subgrid orographic parameters, we construct the orographic parameters, including the subgrid orographic standard deviation, anisotropy, orientation, and slope, that are required as input to the orographic gravity wave drag(OGWD) parameterization. Finally, we introduce the newly constructed orographic parameters into the Yin-He Global Spectral Model(YHGSM), optimize the description of the orographic effect in the model, and improve the simulation of two typical heavy rainfall events in Beijing and Henan.

关键词： subgrid orographic parameters orographic drag heavy rainfall Yin-He Global Spectral Model (YHGSM) parameterization

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An intuitive parameterization method with inherently high-order differentiability for compressor blade sections based on ellipse hierarchical deformation

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Chinese Journal of Aeronautics 2023年第8期36卷 74-90页

作者： Chuanrui SI Jinxin CHENG Zhengqing ZHU Zhitong CHEN Qinglong HAO School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China Zaozhuang Beihang Machine Tool Innovation Research Institute Co. LtdZaozhuang 277500China Ningbo Institute of Technology Beihang UniversityNingbo 315832China

Shape parameterization has a crucial influence on the optimal solution of aerodynamic optimization.This paper proposes a novel parameterization method for compressor blade sections based on the three-level deformation of the ellipse,which simultaneously satisfies the requirements of flexibility,smoothness,intuitiveness,and compactness.In proposed method,the first-level deformation directly controls nine key geometric parameters to construct the blade section profile,and then the second-and third-level deformations are performed respectively to coarsely and finely modify the profile while keeping the key geometric parameters unchanged.These three levels of deformation effectively decompose the design space without destroying the ellipse’s infinite differentiability,allowing designers to work only with intuitive shape-related parameters to design blade sections with inherently high-order continuity.To verify the effectiveness,six existing blade sections are first fitted and then one of them is selected for a three-level optimization.The results show that the geometry and aerodynamic performance of the fitted and the original blade sections are in good agreement,and the loss coefficient of the optimized blade section is reduced by a total of 36.41%,with 27.34%,8.45%,and 0.62%reductions for the first to the third level,respectively.Therefore,the proposed parameterization method facilitates the design of lower-loss and higher-load compressor blade sections.

关键词： Aerodynamics Blade sections Compressors Deformation Ellipse parameterization

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Curvature-Based r-Adaptive Isogeometric Analysis with Injectivity-Preserving Multi-Sided Domain parameterization

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Journal of Systems Science & Complexity 2023年第1期36卷 53-76页

作者： JI Ye WANG Mengyun YU Yingying ZHU Chungang School of Mathematical Sciences Dalian University of TechnologyDalian 116024China Key Laboratory for Computational Mathematics and Data Intelligence of Liaoning Province Dalian 116024China School of Mathematics Liaoning Normal UniversityDalian 116029China

Inspired by the r-refinement method in isogeometric analysis,in this paper,the authors propose a curvature-based r-adaptive isogeometric method for planar multi-sided computational domains parameterized by toric surface patches.The authors construct three absolute curvature metrics of isogeometric solution surface to characterize its gradient information,which is more straightforward and effective.The proposed method takes the internal weights as optimization variables and the resulting parameterization is analysis-suitable and injectivity-preserving with a theoretical guarantee.Several PDEs are solved over multi-sided computational domains parameterized by toric surface patches to demonstrate the effectiveness and efficiency of the proposed method.

关键词： Isogeometric analysis parameterization r-adaptive toric surface patches

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Impact of seepage flow on sediment resuspension by internal solitary waves:parameterization and mechanism

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Journal of Oceanology and Limnology 2023年第2期41卷 444-457页

作者： Zhuangcai TIAN Chao LIU Ziyin REN Xiujun GUO Mingwei ZHANG Xiuhai WANG Lei SONG Yonggang JIA State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Coastal Science and Integrated Management Ministry of Natural ResourcesQingdao 266061China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China

Sediment incipient motion is the first step in sediment resuspension.Previous studies ignored the effect of seepage flow on the mobility of sediment particles and simplified the seabed surface as a rigid boundary.A flume experiment was designed to innovatively divide the seabed into two parts to control the dynamic response of the seabed and control the seepage conditions.In the experiment,the seabed sediments and the amplitude of internal solitary waves(ISWs)were changed to compare and analyze the impact of seepage flow on the sediment resuspension by shoaling ISWs.Moreover,parametric research and verification were carried out.Results indicate that seepage flow can greatly influence fine sand,promote sediment resuspension,and increase the amount of suspension by two times on average.However,seepage flow had a little effect on the suspension of clayey silt and sandy silt.Besides,seepage force was added to the traditional gravity,drag force,and uplift force,and the parameterization of threshold starting shear stress of coarse-grained sediments was developed.The results of this parameterization were verified,and seepage force was critical to parameterization.The threshold starting shear stress was reduced by 54.6%after increasing the seepage force.The physical mechanism of this process corresponded to the vertical reciprocating transient seepage in and out the seabed interface caused by the wave-induced transient excess pore water pressure.This quantitative study on seepage flow for shear stress of coarse-grained sediments induced by ISWs is critical to geohazard assessment.

关键词： internal waves seepage flow sediment resuspension parameterization mechanism

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Modified parameterization for near-inertial waves

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Acta Oceanologica Sinica 2022年第10期41卷 41-53页

作者： Weiqi Hong Lei Zhou Xiaohui Xie Han Zhang Changrong Liang School of Oceanography Shanghai Jiao Tong UniversityShanghai200030China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou310012China Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies Xiamen UniversityXiamen361102China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China

The near-inertial waves(NIWs)are important for energy cascade in the ocean.They are usually significantly reinforced by strong winds,such as typhoon.Due to relatively coarse resolutions in contemporary climate models,NIWs and associated ocean mixing need to be parameterized.In this study,a parameterization for NIWs proposed by Jochum in 2013(J13 scheme),which has been widely used,is compared with the observations in the South China Sea,and the observations are treated as model outputs.Under normal conditions,the J13 scheme performs well.However,there are noticeable discrepancies between the J13 scheme and observations during typhoon.During Typhoon Kalmaegi in 2014,the inferred value of the boundary layer is deeper in the J13 scheme due to the weak near-inertial velocity shear in the vertical.After typhoon,the spreading of NIWs beneath the upper boundary layer is much faster than the theoretical prediction of inertial gravity waves,and this fast process is not rendered well by the J13 scheme.In addition,below the boundary layer,NIWs and associated diapycnal mixing last longer than the direct impacts of typhoon on the sea surface.Since the energy dissipation and diapycnal mixing below the boundary layer are bounded to the surface winds in the J13 scheme,the prolonged influences of typhoon via NIWs in the ocean interior are missing in this scheme.Based on current examination,modifications to the J13 scheme are proposed,and the modified version can reduce the discrepancies in the temporal and vertical structures of diapycnal mixing.

关键词： near-inertial waves parameterization ocean mixing upper ocean boundary layer typhoon

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parameterization of general Z-γ-Z′mixing in an electroweak chiral theory

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Chinese Physics C 2012年第4期36卷 298-306页

作者：张盈王青 School of Science Xi'an Jiaotong University Center for High Energy Physics Tsinghua University Department of Physics Tsinghua University

A new general parameterization with eight mixing parameters among Z, γ and an extra neutral gauge boson Z is proposed and subjected to phenomenological analysis. We show that in addition to the conventional Weinberg angle θW , there are seven other phenomenological parameters, G , ξ, η, θl, θr, r and l, for the most general Z-γ-Z mixings, in which parameter G arises due to the presence of an extra Stueckelberg- type mass coupling. Combined with the conventional Z-Z mass mixing angle θ , the remaining six parameters, ξ, η, θl θ , θr θ , r and l, are caused by general kinetic mixing. In all eight phenomenological parameters, θW , G , ξ, η, θl, θr , r and l, we can determine the Z-Z mass mixing angle θ and the mass ratio MZ/MZ . The Z-γ-Z mixing that we discuss are based on the model-independent description of the extended electroweak chiral Lagrangian （EWCL） previously proposed by us. In addition, we show that there are eight corresponding independent theoretical coefficients in our EWCL, which are fully fixed by our eight phenomenological mixing parameters. We further find that the experimental measurability of these eight parameters does not rely on the extended neutral current for Z , but depends on the Z-Z mass ratio.

关键词： Z boson chiral effective theory parameterization

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parameterization for fitting triangular mesh

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Progress in Natural Science:Materials International 2006年第11期16卷 1214-1221页

作者： LIN Hongwei**, WANG Guojin, LIU Ligang and BAO Hujun(State Key Laboratory of CAD&CG, Zhejiang University, Hangzhou 310027, China) State Key Laboratory of CAD and CG Zhejiang University Hangzhou 310027 China

In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.

关键词： parameterization regular parametric curve grid mesh fitting reverse engineering.

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Understanding primary and secondary sources of ambient oxygenated volatile organic compounds in Shenzhen utilizing photochemical age-based parameterization method

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Journal of Environmental Sciences 2019年第1期31卷 105-114页

作者： Bo Zhu Yu Han Chuan Wang Xiaofeng Huang Shiyong Xia Yingbo Niu Zixuan Yin Lingyan He Key Laboratory for Urban Habitat Environmental Science and Technology School of Environment and Energy Peking University Shenzhen Graduate School

Oxygenated volatile organic compounds(OVOCs) are key intermediates in the atmospheric photooxidation process. To further study the primary and secondary sources of OVOCs,their ambient levels were monitored using a proton-transfer reaction mass spectrometer(PTR-MS) at an urban site in the Pearl River Delta of China. Continuous monitoring campaigns were conducted in the spring, summer, fall, and winter of 2016. Among the six types of OVOC species, the mean concentrations of methanol were the highest in each season(up to 13–20 ppbv), followed by those of acetone, acetaldehyde and acetic acid(approximately 2–4 ppbv), while those of formic acid and methyl ethyl ketone(MEK) were the lowest(approximately 1–2 ppbv). As observed from a diurnal variation chart, the OVOCs observed in Shenzhen may have been affected by numerous factors such as their primary and secondary sources and photochemical consumption. The photochemical age-based parameterization method was used to apportion the sources of ambient OVOCs. Methanol had significant anthropogenic primary sources but negligible anthropogenic secondary sources during all of the seasons. Acetone, MEK and acetic acid were mostly attributed to anthropogenic primary sources during each season with smaller contributions from anthropogenic secondary sources. Acetaldehyde had similar contributions from both anthropogenic secondary and anthropogenic primary sources throughout the year.Meanwhile, anthropogenic primary sources contributed the most to formic acid.

关键词： OVOCs PTR-MS Photochemical age-based parameterization method

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Differentials-Based Segmentation and parameterization for Point-Sampled Surfaces

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Journal of Computer Science & Technology 2007年第5期22卷 749-760页

作者：缪永伟冯结青肖春霞彭群生 A.R.Forrest State Key Laboratory of CAD & CG Zhejiang University Hangzhou 310027China College of ScienceZhejiang University of TechnologyHangzhou 310032China State Key Laboratory of CAD & CG Zhejiang University Hangzhou 310027China School of Computing Sciences University of East Anglia NorwichNR4 7TJU.K.

Efficient parameterization of point-sampled surfaces is a fundamental problem in the field of digital geometry processing. In order to parameterize a given point-sampled surface for minimal distance distortion, a differentialslbased segmentation and parameterization approach is proposed in this paper. Our approach partitions the point-sampled geometry based on two criteria： variation of Euclidean distance between sample points, and angular difference between surface differential directions. According to the analysis of normal curvatures for some specified directions, a new projection approach is adopted to estimate the local surface differentials. Then a k-means clustering （k-MC） algorithm is used for partitioning the model into a set of charts based on the estimated local surface attributes. Finally, each chart is parameterized with a statistical method -- multidimensional scaling （MDS） approach, and the parameterization results of all charts form an atlas for compact storage.

关键词： computer graphics point-sampled surface segmentation parameterization k-means clustering multidi- mensional scaling

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