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Effects of monsoon onset vortex on heat budget in the mixed layer of the Bay of Bengal

Journal of Oceanology and Limnology 2020年第6期38卷 1616-1631页

作者： Effects of monsoon onset vortex on heat budget in the mixed layer of the Bay of BengalXU Kang LIU Boqi LIU Yu WANG Weiqiang HE Zhuoqi State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of SciencesGuangzhou 510301China State Key Laboratory of Severe Weather and Institute of Climate System Chinese Academy of Meteorological SciencesBeijing 100081China Institute of Deep-sea Science and Engineering Chinese Academy of SciencesSanya 572000China University of Chinese Academy of Sciences Beijing 100049China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

We investigated the effects of monsoon onset vortex(MOV)on the mixed layer heat budget in the Bay of Bengal(BOB)in spring 2003 using the reanalysis *** results suggest that the solar radiation flux penetrating the mixed layer and the existence of barrier layer are both able to modulate the effects of MOV on the evolution of sea surface temperature(SST)in the *** to the formation of BOB MOV,the local SST raised quickly due to mass of solar radiation reaching the sea surface under the clear-sky ***,since the mixed layer was shallow before the onset of the Asian summer monsoon(ASM),some solar radiation flux could penetrate to directly heat the deeper water,which partly offset the warming effect of shortwave *** the other hand,the in-situ SST started to cool due to the upwelling of cold water when the MOV generated over the BOB,along with the rapidly increased surface wind speed and its resultant deeper mixed *** the MOV developed and moved northward,the SST tended to decrease remarkably because of the strong upward surface latent heat flux over the BOB ascribed to the wind-evaporation ***,the MOV-related precipitation brought more fresh water into the upper ocean to produce a thicker barrier layer,whose thermal barrier effect damped the cooling effect of entrainment upwelling on the decrease tendency of the BOB *** other words,the thermal barrier effect could slow down the decreasing trend of the BOB SST even after the onset of ASM,which facilitated the further enhancement of the MOV.

关键词： monsoon onset vortex(MOV) Bay of Bengal air-sea interaction mixed layer depth barrier layer thickness heat budget analysis

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Rapid Prediction Model of Equivalent Thermal Conductivity of Plain Weave Fabric in Space Environment

SSRN

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SSRN 2023年

作者： Qin, Jiaxing Wu, Jiawen Mu, Lei Zhang, Biao Li, Jian Xu, Chuanlong National Engineering Research Center of Power Generation Control and Safety School of Energy and Environment Southeast University Nanjing210096 China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China

The prediction of effective thermal conductivity of aerospace insulation materials is crucial for insulation design and radiation characteristics control of space targets. In this paper, a rapid and accurate prediction model is proposed for the effective thermal conductivity of plain weave fabrics in space environments. This model assumes that the cross-sectional shape and bending degree of yarns within aerospace fabrics remain unchanged. To represent the structural characteristics of the plain weave fabric, a dimensionless parameter called "[[EQUATION]]" is defined. numerical simulations are conducted to investigate the effects of fabric structure, temperature, and yarn thermal properties on the effective thermal conductivity of multilayer fabrics. Three parameters are identified as the most influential factors for the effective thermal conductivity of plain weave fabrics: the structural parameter [[EQUATION]], and the axial and radial thermal conductivities of yarns. Based on extensive simulation data, an empirical formula is proposed for the rapid prediction of the effective thermal conductivity of plain weave fabrics. Moreover, polyester, cotton, and wool plain weave fabric samples are tested for their thermal conductivity in a vacuum environment. The predicted results from the empirical formula proposed in this study exhibit a deviation of less than 6% when compared to experimental measurements. This study can provide valuable insights for the design of plain weave fabrics used in aerospace insulation materials. © 2023, The Authors. All rights reserved.

关键词： Yarn

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Elucidating Dominant Factors Affecting Land Surface Hydrological Simulations of the Community Land Model over China

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Advances in Atmospheric sciences 2023年第2期40卷 235-250页

作者： Jianguo LIU Zong-Liang YANG Binghao JIA Longhuan WANG Ping WANG Zhenghui XIE Chunxiang SHI School of Mathematics and Computational Science and Key Laboratory of Intelligent Control Technology for Wuling-Mountain Ecological Agriculture in Hunan ProvinceHuaihua UniversityHuaihuaHunan 418008China Department of Geological Sciences The John A.and Katherine G.Jackson School of GeosciencesUniversity of Texas at AustinAustinTexas 78712-1722USA State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National Meteorological Information Center China Meteorological AdministrationBeijing 100081China

In order to compare the impacts of the choice of land surface model(LSM)parameterization schemes,meteorological forcing,and land surface parameters on land surface hydrological simulations,and explore to what extent the quality can be improved,a series of experiments with different LSMs,forcing datasets,and parameter datasets concerning soil texture and land cover were *** simulations are run for the Chinese mainland on 0.1°×0.1°grids from 1979 to 2008,and the simulated monthly soil moisture(SM),evapotranspiration(ET),and snow depth(SD)are then compared and assessed against *** results show that the meteorological forcing is the most important factor governing *** that,SM seems to be also very sensitive to soil texture information;SD is also very sensitive to snow parameterization scheme in the *** Community Land Model version 4.5(CLM4.5),driven by newly developed observation-based regional meteorological forcing and land surface parameters(referred to as CMFD_CLM4.5_NEW),significantly improved the simulations in most cases over the Chinese mainland and its eight *** increased the correlation coefficient values from 0.46 to 0.54 for the SM modeling and from 0.54 to 0.67 for the SD simulations,and it decreased the root-mean-square error(RMSE)from 0.093 to 0.085 for the SM simulation and reduced the normalized RMSE from 1.277 to 0.201 for the SD *** study indicates that the offline LSM simulation using a refined LSM driven by newly developed observation-based regional meteorological forcing and land surface parameters can better model reginal land surface hydrological processes.

关键词： hydrological simulations land surface model meteorological forcing land surface parameters uncertainty

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Individual Identification Algorithm of Known Emitters Based on Lightweight Binary Channels Neural Network

Individual Identification Algorithm of Known Emitters Based ...

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IEEE International Symposium on Information (IT) in Medicine and Education, ITME

作者： Jingpeng Gao Xia Song Lu Gao College of Information and Communication Engineering Harbin Engineering University Harbin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

Aiming at the problem that the traditional specific emitter identification method has poor feature extraction ability and limited recognition effect, this paper proposes a known specific emitter identification algorithm based on the LBCNet (the Lightweight Binary Channels Net). The algorithm uses bispectrum and cyclic spectrum to highlight the unintentional information in the pulse. Then, it combines the idea of depthwise separable convolution to design the LBCNet to realize adaptive feature extraction, fusion, and classification. Finally, it integrates the attention mechanism to highlight the effective information of the image, enhance the neural network’s learning ability and improve the identification performance of specific emitters. The simulation results show that the recognition rate of the proposed algorithm is as high as 94.53% at 0dB, which has good engineering practical value and can be applied to the field of electronic reconnaissance.

关键词： Convolution Simulation Neural networks Education Radar Reconnaissance Feature extraction

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Recursive Evaluation of Sure for Total Variation Denoising

Recursive Evaluation of Sure for Total Variation Denoising

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Feng Xue Thierry Blu Jiaqi Liu Xia Ai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 China Dept. of Electronic Engineering The Chinese University of Hong Kong Shatin N.T. Hong Kong

ISBN: (纸本)9781538646595

Recently, total variation (TV)-based regularization has become a standard technique for signal denoising. The reconstruction quality is generally sensitive to the value of regularization parameter. In this work, based on Cham-bolle's algorithm, we develop two data-driven optimization schemes based on minimization of Stein's unbiased risk estimate (SURE)-statistically equivalent to mean squared error (MSE). First, we propose a recursive evaluation of SURE to monitor the estimation error during Chambolle's iteration;the optimal value is then identified by the minimum SURE. Second, for fast optimization, we perform alternating update between regularization parameter and solution within Chambolle's iteration. We exemplify the proposed methods with both 1-D and 2-D signal denoising. numerical experiments show that the proposed methods lead to highly accurate estimate of regularization parameter and nearly optimal denoising performance.

关键词： Signal denoising total variation (TV) Stein's unbiased risk estimate (SURE) Chambolle's algorithm

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The Effects of Base Shape on Cone Scattering Feature

The Effects of Base Shape on Cone Scattering Feature

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yongtao Shui Shengjun Zhang Hang Song Lei Mu Xianglin Zhang Yuning Zhang Yichun Cui Weidong Wang Mingliang Wang Ligen Cai Yinfang Xu Song Chai Jiaqi Liu Chao Dong Fengju Wang Zhengyu Yong Chunshou Shao Minghao Wang Zhaohui Qi Yuan Sun Chenxin Sun Beijing Institute of Space Long March Vehicle Beijing China National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Institute of Survival Technology effectiveness Evaluation of Flying Vehicle Beijing China

Recent days, radar cross section reduction(RCSR) of objects have attracted much interest as more and more wideband radar were used to detect low observable weapon platforms. Among the low observation technologies, shaping plays an important role. This paper focused on the effect of basement shape on the scattering of a cone-like object, and some basement shape better for low radar cross section design for around tip incident angle were analyzed.

关键词： Geometry Radar cross-sections Shape Surface waves Weapons Electromagnetic scattering Nose

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Modulation recognition of emitter signals based on SDAE-ODCNN

Modulation recognition of emitter signals based on SDAE-ODCN...

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IET International Radar Conference (IET IRC 2020)

作者： X. Wang J. Gao L. Gao F. Wang Harbin Engineering University College of Information and Communication Engineering Harbin China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In order to improve the recognition rate of emitter signals modulation under low signal noise ratio (SNR), an end-to-end method based on the stacked denoising autoencoder (SDAE) - one dimensional convolutional neural network (ODCNN) is proposed in this paper. The SADE-ODCNN is designed in this method and trained through a two-step training. In the SDAE-ODCNN model, the encoder of the SDAE can extract the denoised and compressed features of the received emitter signals. Then the ODCNN can further extract features to realize the recognition. The simulation results show that the average recognition rate of the method can reach 0.94 under 0dB. Thus the proposed method has a good application in the field of emitter signals modulation recognition.

关键词： radar computing modulation feature extraction neural nets image denoising learning (artificial intelligence) image classification

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Advances in the Researches of the Middle and Upper Atmosphere in China in 2014-2016

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空间科学学报 2016年第5期36卷 738-752页

作者： CHEN Zeyu XU Jiyao HU Xiong CHEN Hongbin CHEN Wen WEI Ke BIAN Jianchun TIAN Wenshou ZHANG Shaodong REN Rongcai DOU Xiankang Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 National Space Science Center Chinese Academy of Sciences Beijing 100190 Institute of Atmospheric Physics Chinese Academy of Scienees Beijing 100029 School of Atmospheric Sciences Lanzhou University Lanzhou 730000 School of Electronic Information Wuhan University Wuhan 430072 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 School of Earth and Space Sciences University of Science and Technology of China Hefei 230026

In this report the research results by Chinese scientists in 2014—2016 are *** focuses are placed on the researches of the middle and upper atmosphere,specifically the researches associated with ground-based observation capabihty development,dynamical processes,and properties of circulation and chemistry-climate coupling of the middle atmospheric layers.

关键词：中高层大气中国科学家研究成果观察能力耦合特性大气化学中间层气候

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A Compound THz Meta-surface Absorber with Polarization Insensitivity and Angular Stability

A Compound THz Meta-surface Absorber with Polarization Insen...

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IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Kai Wang Hailiang Zhu Ganyu Liu Jinchao Mou Pei Zheng Gao Wei Northwestern Polytechnical University School of Electronics and Information Xi'an Shaanxi CN Beijing Research Institute of Telemetry Beijing CN The National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing CN

In this paper, a wideband terahertz meta-surface absorber with ultra-thin thickness is proposed. The meta-surface unit cell is composed of four-square unit cells in two different sizes. The the absorption higher than 90% from 3.24 to 3.98THz is achieved which can be regarded as a perfect terahertz absorber. Due to the symmetrical layout of meta-surface unit cell, the absorption spectrum can be maintained for any linear polarized terahertz wave, and the absorptance can be kept higher than 80% while the incident angle increases before 45°. Furthermore, the thermal response is calculated to be 0.23 $\mathbf{K} \cdot{\mathbf{m}\mathbf{m}^{2}/ \upmu \mathbf{W}}$ that well suited the requirements of FPA detectors.

关键词： Sensitivity Absorption Layout Detectors Stability analysis Compounds Thermal stability

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A review of progress in coupled ocean-atmosphere model developments for ENSO studies in China

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Journal of Oceanology and Limnology 2020年第4期38卷 930-961页

作者： ZHANG Rong-Hua YU Yongqiang SONG Zhenya REN Hong-Li TANG Youmin QIAO Fangli WU Tongwen GAO Chuan HU Junya TIAN Feng ZHU Yuchao CHEN Lin LIU Hailong LIN Pengfei WU Fanghua WANG Lin Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Laboratory for Ocean and Climate Dynamics Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100049China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Key Laboratory of Marine Science and Numerical Modeling(MASNUM) Ministry of Natural ResourcesQingdao 266061China National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology Qingdao 266061China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Laboratory for Climate Studies and CMA-NJU Joint Laboratory for Climate Prediction Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Environmental Science and Engineering University of Northern British ColumbiaBritish Columbia V2N 4Z9Canada State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Key Laboratory of Meteorological Disaster Ministry of Education(KLME)and Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science and TechnologyNanjing 210044China Beijing Climate Center China Meteorological AdministrationBeijing 100081China

El Nino-Southern Oscillation(ENSO) is the strongest interannual signal that is producedby basinscale processes in the tropical Pacific,with significant effects on weather and climate *** the past,extensive and intensive international efforts have been devoted to coupled model developments for ENSO studies.A hierarchy of coupled ocean-atmo sphere models has been formulated;in terms of their complexity,they can be categorized into intermediate coupled models(ICMs),hybrid coupled models(HCMs),and fully coupled general circulation models(CGCMs).ENSO modeling has made significant progress over the past decades,reaching a stage where coupled models can now be used to successfully predict ENSO events 6 months to one year in ***,ENSO exhibits great diversity and complexity as observed in nature,which still cannot be adequately captured by current state-of-the-art coupled models,presenting a challenge to ENSO *** primarily reviewed the long-term efforts in ENSO modeling continually and steadily made at different institutions in China;some selected representative examples are presented here to review the current status of ENSO model developments and applications,which have been actively pursued with noticeable progress being made *** ENSO simulations are very sensitive to model formulations and process representations etc.,dedicated efforts have been devoted to ENSO model developments and ***,different ocean-atmosphere coupled models have been available in China,which exhibit good model performances and have already had a variety of applications to climate modeling,including the Coupled Model Intercomparison Project Phase 6(CMIP6).Nevertheless,large biases and uncertainties still exist in ENSO simulations and predictions,and there are clear rooms for their improvements,which are still an active area of researches and ***,model performances of ENSO simulations are assessed in terms of advantages and disadvantage

关键词： El Niño-Southern Oscillation(ENSO) coupled ocean-atmosphere models simulations and predictions model biases and uncertainties

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