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On variance of exponents for isolated surface singularities with modality ≤ 2 In Memory of Professor Philip Wagreich
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作者 YAU Stephen S.T. ZUO HuaiQing 《Science China Mathematics》 SCIE 2014年第1期31-41,共11页
Using the theory of the mixed Hodge structure one can define a notion of exponents of a singularity.In 2000,Hertling proposed a conjecture about the variance of the exponents of a singularity.Here,we prove that the He... Using the theory of the mixed Hodge structure one can define a notion of exponents of a singularity.In 2000,Hertling proposed a conjecture about the variance of the exponents of a singularity.Here,we prove that the Hertling conjecture is true for isolated surface singularities with modality ≤ 2. 展开更多
关键词 singularities modality exponents
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NONTRIVIAL SOLUTION FOR A CLASS OF SEMILINEAR BIHARMONIC EQUATION INVOLVING CRITICAL EXPONENTS 被引量:9
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作者 姚仰新 王荣鑫 沈尧天 《Acta Mathematica Scientia》 SCIE CSCD 2007年第3期509-514,共6页
In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequal... In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequality. 展开更多
关键词 Biharmonic equation critical exponent singular term nontrivial solution Sobolev-Hardy inequality
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EXISTENCE OF MULTIPLE SOLUTIONS FOR SINGULAR QUASILINEAR ELLIPTIC SYSTEM WITH CRITICAL SOBOLEV-HARDY EXPONENTS AND CONCAVE-CONVEX TERMS 被引量:6
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作者 李圆晓 高文杰 《Acta Mathematica Scientia》 SCIE CSCD 2013年第1期107-121,共15页
The main purpose of this paper is to establish the existence of multiple solutions for singular elliptic system involving the critical Sobolev-Hardy exponents and concave-convex nonlinearities. It is shown, by means o... The main purpose of this paper is to establish the existence of multiple solutions for singular elliptic system involving the critical Sobolev-Hardy exponents and concave-convex nonlinearities. It is shown, by means of variational methods, that under certain conditions, the system has at least two positive solutions. 展开更多
关键词 singular elliptic system concave-convex nonlinearities positive solution Nehari manifold critical Sobolev-Hardy exponent
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INFINITELY MANY SOLUTIONS FOR A SINGULAR ELLIPTIC EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENTS IN R^N 被引量:1
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作者 贺小明 邹文明 《Acta Mathematica Scientia》 SCIE CSCD 2010年第3期830-840,共11页
In this article, we study the existence of multiple solutions for the singular semilinear elliptic equation involving critical Sobolev-Hardy exponents -△μ-μ|x|^2^-μ=α|x|^s^-|μ|^2*(s)-2u+βα(x)|u|^... In this article, we study the existence of multiple solutions for the singular semilinear elliptic equation involving critical Sobolev-Hardy exponents -△μ-μ|x|^2^-μ=α|x|^s^-|μ|^2*(s)-2u+βα(x)|u|^r-2u,x∈R^n. By means of the concentration-compactness principle and minimax methods, we obtain infinitely many solutions which tend to zero for suitable positive parameters α,β. 展开更多
关键词 Singular elliptic equation Multiple solutions Critical Sobolev-Hardy exponent Minimax method
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EXISTENCE RESULTS FOR DEGENERATE ELLIPTIC EQUATIONS WITH CRITICAL CONE SOBOLEV EXPONENTS 被引量:1
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作者 范海宁 刘晓春 《Acta Mathematica Scientia》 SCIE CSCD 2014年第6期1907-1921,共15页
In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory ... In this paper, we study the existence result for degenerate elliptic equations with singular potential and critical cone sobolev exponents on singular manifolds. With the help of the variational method and the theory of genus, we obtain several results under different conditions. 展开更多
关键词 existence results variational method critical cone Sobolev exponent singular potential
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Five Nontrivial Solutions of p-Laplacian Problems Involving Critical Exponents and Singular Cylindrical Potential 被引量:1
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作者 Mohammed el Mokhtar ould el Mokhtar 《Journal of Physical Science and Application》 2015年第2期163-172,共10页
In this paper, we establish the existence of at least five distinct solutions to a p-Laplacian problems involving critical exponents and singular cylindrical potential, by using the Nehari manifold, concentration-comp... In this paper, we establish the existence of at least five distinct solutions to a p-Laplacian problems involving critical exponents and singular cylindrical potential, by using the Nehari manifold, concentration-compactness principle and mountain pass theorem 展开更多
关键词 Nehari manifold concentration-compacmess principle critical Hardy-Sobolev exponent singular cylindrical potential mountain pass theorem nontrivial cylindrical solution.
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CRITICAL EXPONENTS AND CRITICAL DIMENSIONS FOR NONLINEAR ELLIPTIC PROBLEMS WITH SINGULAR COEFFICIENTS
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作者 王莉 汪继秀 《Acta Mathematica Scientia》 SCIE CSCD 2014年第5期1603-1618,共16页
Let B1 С RN be a unit ball centered at the origin. The main purpose of this paper is to discuss the critical dimension phenomenon for radial solutions of the following quasilinear elliptic problem involving critical ... Let B1 С RN be a unit ball centered at the origin. The main purpose of this paper is to discuss the critical dimension phenomenon for radial solutions of the following quasilinear elliptic problem involving critical Sobolev exponent and singular coefficients:{-div(|△u|p-2△u)=|x|s|u|p*(s)-2u+λ|x|t|u|p-2u, x∈B1, u|σB1 =0, where t, s〉-p, 2≤p〈N, p*(s)= (N+s)pN-p andλ is a real parameter. We show particularly that the above problem exists infinitely many radial solutions if the space dimension N 〉p(p-1)t+p(p2-p+1) andλ∈(0,λ1,t), whereλ1,t is the first eigenvalue of-△p with the Dirichlet boundary condition. Meanwhile, the nonexistence of sign-changing radial solutions is proved if the space dimension N ≤ (ps+p) min{1, p+t/p+s}+p2p-(p-1) min{1, p+tp+s} andλ〉0 is small. 展开更多
关键词 singular coefficients radial solution critical exponent p-Laplace equations
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Vector-valued Inequalities for Commutators of Singular Integrals on Herz Spaces with Variable Exponents
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作者 WANG LI-WEI QU MENG +1 位作者 SHU LI-SHENG Ji You-qing 《Communications in Mathematical Research》 CSCD 2017年第4期363-376,共14页
Based on the theory of variable exponents and BMO norms, we prove the vector-valued inequalities for commutators of singular integrals on both homogeneous and inhomogeneous Herz spaces where the two main indices are v... Based on the theory of variable exponents and BMO norms, we prove the vector-valued inequalities for commutators of singular integrals on both homogeneous and inhomogeneous Herz spaces where the two main indices are variable exponents.Furthermore, we show that a wide class of commutators generated by BMO functions and sublinear operators satisfy vector-valued inequalities. 展开更多
关键词 variable exponent Herz spaces COMMUTATOR singular integral
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Existence of Solutions to Elliptic Equations with Variable Exponents and a Singular Term
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作者 Chen Xu-sheng 《Communications in Mathematical Research》 CSCD 2016年第2期185-192,共8页
The purpose of this paper is to study a class of elliptic equations with variable exponents. By using the method of regularization and a priori estimates, we obtain the existence of weak solutions to these problems.
关键词 variable exponent SINGULAR EXISTENCE
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Boundedness of Multilinear Caldern–Zygmund Singular Operators on Morrey–Herz Spaces with Variable Exponents 被引量:15
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作者 Yan LU Yue Ping ZHU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2014年第7期1180-1194,共15页
In this paper, we introduce Morrey-Herz spaces MKq.p(·)α(·),λ with variable exponents α(·) and p(·), and prove the boundedness of multilinear Calderdn-Zygmund singular operators on the ... In this paper, we introduce Morrey-Herz spaces MKq.p(·)α(·),λ with variable exponents α(·) and p(·), and prove the boundedness of multilinear Calderdn-Zygmund singular operators on the product of these spaces. 展开更多
关键词 Morrey-Herz spaces variable exponents multilinear Calder6n-Zygmund singular operators
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基于声发射的木材裂缝数量辨识研究
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作者 张志恒 李明 +5 位作者 沈志辉 陈楚敏 方赛银 杜坤 杨龙飞 邓婷婷 《森林工程》 北大核心 2025年第1期59-66,共8页
针对木材裂缝缺陷,提出一种基于声发射的木材裂缝数量识别方法。首先,在试件上人为依次制作1 mm×9 mm(长×高)的4条裂缝,在裂缝的一侧通过折铅的方式产生声发射(acoustic emission,AE)信号,另一侧放置传感器,信号采样频率设置... 针对木材裂缝缺陷,提出一种基于声发射的木材裂缝数量识别方法。首先,在试件上人为依次制作1 mm×9 mm(长×高)的4条裂缝,在裂缝的一侧通过折铅的方式产生声发射(acoustic emission,AE)信号,另一侧放置传感器,信号采样频率设置为2 MHz。然后,通过粒子群算法(particle swarm optimization,PSO)确定变分模态分解(variational mode decoposition,VMD)的分解层数K和惩罚因子α,并将原始信号分解为具有不同频率的本征模态(intrinsic mode function,IMF)。接着,随机选择5组信号进行VMD分解,并对分解后的IMF构成的矩阵进行奇异值分解(singular value decomposition,SVD),得到相应的奇异值向量,再由5组奇异值向量组成标准矩阵。最后,由测得的AE信号,分别与标准矩阵计算马氏距离,并依据最小判别原则,判定裂缝数量。结果表明,PSO-VMD-SVD方法能够方便提取出AE信号特征,并通过计算马氏距离进行裂缝数量判别,判别正确率为92%。 展开更多
关键词 声发射 变分模态分解 奇异值分解 马氏距离 木材裂缝缺陷
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Propagations of singularities in a parabolic system with coupling nonlocal sources 被引量:10
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作者 ZHANG He KONG LingHua ZHENG SiNing 《Science China Mathematics》 SCIE 2009年第1期181-194,共14页
This paper deals with propagations of singularities in solutions to a parabolic system coupled with nonlocal nonlinear sources. The estimates for the four possible blow-up rates as well as the boundary layer profiles ... This paper deals with propagations of singularities in solutions to a parabolic system coupled with nonlocal nonlinear sources. The estimates for the four possible blow-up rates as well as the boundary layer profiles are established. The critical exponent of the system is determined also. 展开更多
关键词 nonlocal nonlinear sources parabolic systems critical exponent blow-up rate boundary layer profile propagation of singularity 35K55 35B40
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Boundedness of multilinear singular integrals on central Morrey spaces with variable exponents 被引量:1
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作者 Hongbin WANG Jingshi XU Jian TAN 《Frontiers of Mathematics in China》 SCIE CSCD 2020年第5期1011-1034,共24页
We prove the boundedness for a class of multi-sublinear singular integral operators on the product of central Morrey spaces with variable exponents.Based on this result,we obtain the boundedness for the multilinear si... We prove the boundedness for a class of multi-sublinear singular integral operators on the product of central Morrey spaces with variable exponents.Based on this result,we obtain the boundedness for the multilinear singular integral operators and two kinds of multilinear singular integral commutators on the above spaces. 展开更多
关键词 Multilinear singular integral variable exponent central Morrey space
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On the Weighted Elliptic Problems Involving Multi-singular Potentials and Multi-critical Exponents 被引量:1
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作者 Dong Sheng KANG 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2009年第3期435-444,共10页
Suppose Ω belong to R^N(N≥3) is a smooth bounded domain,ξi∈Ω,0〈ai〈√μ,μ:=((N-1)/2)^2,0≤μi〈(√μ-ai)^2,ai〈bi〈ai+1 and pi:=2N/N-2(1+ai-bi)are the weighted critical Hardy-Sobolev exponents, i ... Suppose Ω belong to R^N(N≥3) is a smooth bounded domain,ξi∈Ω,0〈ai〈√μ,μ:=((N-1)/2)^2,0≤μi〈(√μ-ai)^2,ai〈bi〈ai+1 and pi:=2N/N-2(1+ai-bi)are the weighted critical Hardy-Sobolev exponents, i = 1, 2,..., k, k ≥ 2. We deal with the conditions that ensure the existence of positive solutions to the multi-singular and multi-critical elliptic problem ∑i=1^k(-div(|x-ξi|^-2ai△↓u)-μiu/|x-ξi|^2(1+ai)-u^pi-1/|x-ξi|^bipi)=0with Dirichlet boundary condition, which involves the weighted Hardy inequality and the weighted Hardy-Sobolev inequality. The results depend crucially on the parameters ai, bi and #i, i -- 1, 2,..., k. 展开更多
关键词 multi-singular multi-critical weighted elliptic problem weighted Hardy-Sobolev exponent
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基于改进经验小波变换的海洋平台结构模态参数自动识别方法
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作者 冷建成 刁凯欣 +1 位作者 庞哲 冯慧玉 《振动与冲击》 EI CSCD 北大核心 2024年第7期196-204,共9页
针对经验小波变换(empirical wavelet transform,EWT)方法在处理低信噪比信号中频谱分割边界容易产生误判的问题,提出了一种改进经验小波变换(improved empirical wavelet transform,IEWT)的结构模态参数自动识别方法。首先计算信号的... 针对经验小波变换(empirical wavelet transform,EWT)方法在处理低信噪比信号中频谱分割边界容易产生误判的问题,提出了一种改进经验小波变换(improved empirical wavelet transform,IEWT)的结构模态参数自动识别方法。首先计算信号的互功率谱矩阵,采用奇异值分解(SVD)及尺度空间(SSPP)方法确定频谱的分割边界,将信号分解为若干固有模态函数(IMF)分量,再结合随机减量技术(RDT)和希尔伯特变换(HT)实现模态参数的自动识别。使用IEWT方法对自由振动响应信号及ASCE Benchmark模型信号进行模态参数识别,并分别与EWT方法、基于自回归功率谱的经验小波变换(AR-EWT)方法及小波变换(WT)方法进行对比,结果表明IEWT方法能够自适应确定频谱分割边界,对结构的频率及阻尼比等模态参数具有较高的识别精度;进一步将该方法应用到实验室海洋平台模型的模态参数识别中,证明该方法可用于复杂噪声环境下的低频结构的模态参数识别。 展开更多
关键词 经验小波变换(EWT) 奇异值分解(SVD) 尺度空间 模态参数自动识别 海洋平台
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基于PE-CEEMD-SVD的Φ-OTDR信号降噪方法
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作者 姚国珍 李炳峰 谷元宇 《半导体光电》 CAS 北大核心 2024年第4期662-668,共7页
为实现相位敏感光时域反射仪中相位信号的精确测量,提出了一种基于排列熵算法的互补集合经验模态分解联合奇异值分解的新型降噪方法(PE-CEEMD-SVD)。首先,对含有噪声的相位信号进行CEEMD分解,得到一系列频率不同的IMF分量;然后,将PE算... 为实现相位敏感光时域反射仪中相位信号的精确测量,提出了一种基于排列熵算法的互补集合经验模态分解联合奇异值分解的新型降噪方法(PE-CEEMD-SVD)。首先,对含有噪声的相位信号进行CEEMD分解,得到一系列频率不同的IMF分量;然后,将PE算法和相关系数机制相结合,保留较大相关的有用分量,对较小相关的噪声分量使用SVD算法进行二次降噪;最后将两次降噪后保留下来的有用分量进行重构。仿真和实验结果表明,相较于EMD、EEMD和CEEMD降噪方法,该方法可获得更高信噪比的信号,有利于相位信号的精确测量。 展开更多
关键词 相位敏感光时域反射仪 排列熵 互补集合经验模态分解 奇异值分解 信噪比
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KSS1536型空间受限原煤分级筛的研制与应用
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作者 徐学卫 《选煤技术》 CAS 2024年第3期66-69,共4页
为解决空间受限原煤分级筛的安装技术难题,设计研制了一种基于重心偏移原理的KSS-1536型原煤分级筛,并详细介绍了其筛分原理、筛板结构、筛机材质及应用效果。该型筛机采用了重心偏移技术,可促使物料迅速分层,避免筛机入料端物料堆积,... 为解决空间受限原煤分级筛的安装技术难题,设计研制了一种基于重心偏移原理的KSS-1536型原煤分级筛,并详细介绍了其筛分原理、筛板结构、筛机材质及应用效果。该型筛机采用了重心偏移技术,可促使物料迅速分层,避免筛机入料端物料堆积,同时排料端物料运动速度慢,有利于延长筛分时间、提高筛分效率;采用空间阶梯形冲孔筛板,具备常规冲孔筛板和梳齿阶梯筛板的优点,可增加有效筛分面积,并使大颗粒物料不易堵孔、细颗粒物料不易糊孔;筛机材质的性能优于Q355,而应力分析显示筛机所受最大应力为36.9 MPa,发生在激振梁上,筛箱整体及各关键部件的刚度和强度均满足设计要求。应用效果表明:KSS1536型原煤分级筛可在空间受限的情况下使用,应用于平顶山八矿选煤厂智能干选后物料的分级作业,处理量可达到300 t/h,筛分效率可达90%;同时能够长时间连续稳定运行,日常维护方便。该设备的成功研制与应用,为空间受限条件下原煤分级筛的选型和工艺布置提供了新的思路。 展开更多
关键词 筛分 原煤分级筛 空间受限 重心偏移 空间筛板 模态分析 抛掷指数 筛分效率
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考虑声-振模态结合的抽水蓄能机组轴承故障诊断
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作者 胡列豪 巩宇 +3 位作者 张勇军 安禹铮 蒋崇颖 廖美英 《电力系统保护与控制》 EI CSCD 北大核心 2024年第11期1-10,共10页
为解决抽水蓄能机组轴承磨损故障难以监测和识别的问题,提出一种结合声振数据的双模态神经网络机组轴承诊断模型。首先分析了抽水蓄能机组声振特性,融合相似软阈值对奇异值分解去噪方法进行改进,有效消除非接触式传感器固有噪声干扰。... 为解决抽水蓄能机组轴承磨损故障难以监测和识别的问题,提出一种结合声振数据的双模态神经网络机组轴承诊断模型。首先分析了抽水蓄能机组声振特性,融合相似软阈值对奇异值分解去噪方法进行改进,有效消除非接触式传感器固有噪声干扰。其次提出逆巴克频谱变换方法,并结合巴克频谱变换和格拉姆角和场变换等特征工程技术,提取机组轴承的声纹和振动特征图。通过融合相对位置编码的自注意力机制和深度可分离卷积,建立特征图传递网络。同时运用多头自注意力机制和双向长短期记忆网络搭建了时序数据传递网络,并以平行网格架构构建了机组轴承故障诊断模型。实验对比分析表明,所提方法具有较高的故障识别准确率,为抽水蓄能电站机组轴承监测问题提供了有效的解决途径。 展开更多
关键词 抽水蓄能机组 声-振模态 奇异值分解 特征工程 故障诊断
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随机激励作用下船舶横摇运动的奇异非混沌动力学
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作者 何智超 乐源 +1 位作者 李高磊 刘润 《动力学与控制学报》 2024年第1期52-59,共8页
基于一类规则横浪作用下的单自由度船舶横摇运动模型,考虑恢复力矩和阻尼力矩的非线性因素,以一低干舷船模为例,利用龙格库塔法求解了横摇运动方程,通过时间庞加莱截面绘制了系统的分岔图;考虑其受随机风荷载扰动下不同周期吸引子演变... 基于一类规则横浪作用下的单自由度船舶横摇运动模型,考虑恢复力矩和阻尼力矩的非线性因素,以一低干舷船模为例,利用龙格库塔法求解了横摇运动方程,通过时间庞加莱截面绘制了系统的分岔图;考虑其受随机风荷载扰动下不同周期吸引子演变成奇异非混沌吸引子的具体过程,发现周期激励系统在随机激励扰动下同样存在奇异非混沌吸引子,且当分岔参数离混沌区域越远,所需要随机激励的幅值越大才能诱发奇异非混沌吸引子.通过最大李雅普诺夫指数验证吸引子的非混沌性;采用奇异连续谱和分形图刻画吸引子的奇异性. 展开更多
关键词 船舶横摇 随机激励 奇异非混沌 李雅普诺夫指数 奇异连续谱
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An improved wind quality control for the China-France Oceanography Satellite (CFOSAT) scatterometer
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作者 Xiaoheng Mou Wenming Lin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第5期100-109,共10页
Quality control(QC)is an essential procedure in scatterometer wind retrieval,which is used to distinguish good-quality data from poor-quality wind vector cells(WVCs)for the sake of wind applications.The current wind p... Quality control(QC)is an essential procedure in scatterometer wind retrieval,which is used to distinguish good-quality data from poor-quality wind vector cells(WVCs)for the sake of wind applications.The current wind processor of the China-France Oceanography Satellite(CFOSAT)scatterometer(CSCAT)adopts a maximum likelihood estimator(MLE)-based QC method to filter WVCs affected by geophysical noise,such as rainfall and wind variability.As the first Ku-band rotating fan-beam scatterometer,CSCAT can acquire up to 16 observations over a single WVC,giving abundant information with diverse incidence/azimuth angles,as such its MLE statistical characteristics may be different from the previous scatterometers.In this study,several QC indicators,including MLE,its spatially averaged value(MLE_(m)),and the singularity exponents(SE),are analyzed using the collocated Global Precipitation Mission rainfall data as well as buoy data,to compare their sensitivity to rainfall and wind quality.The results show that wind error characteristics of CSCAT under different QC methods are similar to those of other Ku-band scatterometers,i.e.,SE is more suitable than other parameters for the wind QC at outer-swath and nadir regions,while MLE_(m) is the best QC indicator for the sweet region WVCs.Specifically,SE is much more favorable than others at high wind speeds.By combining different indicators,an improved QC method is developed for CSCAT.The validation with the collocated buoy data shows that it accepts more WVCs,and in turn,improves the quality control of CSCAT wind data. 展开更多
关键词 China-France Oceanography Satellite(CFOSAT) SCATTEROMETER winds quality control(QC) singularity exponent(SE)
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