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Global parameter estimation of the Cochlodinium polykrikoides model using bioassay data
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作者 CHO Hong-Yeon PARK Kwang-Soon KIM Sung 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第2期39-45,共7页
Cochlodinium polykrikoides is a notoriously harmful algal species that inflicts severe damage on the aquacultures of the coastal seas of Korea and Japan. Information on their expected movement tracks and boundaries of... Cochlodinium polykrikoides is a notoriously harmful algal species that inflicts severe damage on the aquacultures of the coastal seas of Korea and Japan. Information on their expected movement tracks and boundaries of influence is very useful and important for the effective establishment of a reduction plan. In general, the information is supported by a red-tide(a.k.a algal bloom) model. The performance of the model is highly dependent on the accuracy of parameters, which are the coefficients of functions approximating the biological growth and loss patterns of the C. polykrikoides. These parameters have been estimated using the bioassay data composed of growth-limiting factor and net growth rate value pairs. In the case of the C. polykrikoides, the parameters are different from each other in accordance with the used data because the bioassay data are sufficient compared to the other algal species. The parameters estimated by one specific dataset can be viewed as locally-optimized because they are adjusted only by that dataset. In cases where the other one data set is used, the estimation error might be considerable. In this study, the parameters are estimated by all available data sets without the use of only one specific data set and thus can be considered globally optimized. The cost function for the optimization is defined as the integrated mean squared estimation error, i.e., the difference between the values of the experimental and estimated rates. Based on quantitative error analysis, the root-mean squared errors of the global parameters show smaller values, approximately 25%–50%, than the values of the local parameters. In addition, bias is removed completely in the case of the globally estimated parameters. The parameter sets can be used as the reference default values of a red-tide model because they are optimal and representative. However, additional tuning of the parameters using the in-situ monitoring data is highly required.As opposed to the bioassay data, it is necessary because the bioassay data have limitations in terms of the in-situ coastal conditions. 展开更多
关键词 global and local estimation gain and loss parameters Cochlodinium polykrikoides bioassay data model performance
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分布式水文模型在高原山地流域的研究与应用进展
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作者 敖天其 刘臻 +5 位作者 吴玲玲 卢泽华 郭立 李海潮 李红霞 周理 《高原山地气象研究》 2025年第3期14-23,共10页
高原山地流域受到垂直气候梯度与复杂下垫面条件的协同调控,其水文过程呈现显著的时空异质性特征,导致传统水文模型难以精准模拟和预测。分布式水文模型兼具网格空间离散化与产汇流过程物理机制约束等优势,可模拟气象-下垫面复杂互馈过... 高原山地流域受到垂直气候梯度与复杂下垫面条件的协同调控,其水文过程呈现显著的时空异质性特征,导致传统水文模型难以精准模拟和预测。分布式水文模型兼具网格空间离散化与产汇流过程物理机制约束等优势,可模拟气象-下垫面复杂互馈过程所驱动的水文过程,已在高原山地流域的径流过程等水文模拟、预报中得到广泛应用。本文首先综述了分布式水文模型在高原山地流域的应用进展:在模型结构层面,实现了冻土水热耦合、冰川动力过程等模块的改进与多过程集成;融合了多源遥感、再分析等网格产品与地面观测,显著提升了输入数据的精度和时空覆盖度;发展了参数区域化函数或参数转移函数及遥感观测约束的率定技术,由此提升缺资料高原山地流域的分布式水文模拟。其次,本文梳理了分布式水文模型在高原山地流域降雨径流模拟、冰川融雪过程模拟、土壤侵蚀评估及气候/土地利用的水文响应中的关键成果。同时发现,当前高原山地流域分布式水文模拟仍面临冰川动力学机制刻画不足、冻土-生态-水文耦合薄弱及高寒区参数不确定性较大等诸多挑战。最后,论文倡议后续研究需深化水-热-碳地表协同过程机理、发展机器学习辅助或基于下垫面物理特性的参数网格化自适应技术、构建多模型-多数据集成框架,以进一步提升高原山地流域复杂水文过程的模拟预报精度与时效性,为高原生态屏障功能维护与水安全战略提供科技支撑。 展开更多
关键词 分布式水文模型 高原山地流域 模型结构与参数值 输入数据 研究应用进展 挑战与展望
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中国业务数值天气预报自主发展中的理论和方法创新
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作者 沈学顺 苏勇 +8 位作者 李兴良 韩威 杨俊 马占山 刘永柱 张旭 唐杰 陈贤 翁富忠 《气象》 北大核心 2025年第11期1293-1320,共28页
数值天气预报是天气预报业务和防灾减灾的核心科技,是衡量国家气象现代化水平的关键标志。在我国数值天气预报的自主创新历程中,以全球/区域同化预报系统(GRAPES)为核心的全面业务体系的建立,是具有里程碑意义的事件,标志着从技术引进... 数值天气预报是天气预报业务和防灾减灾的核心科技,是衡量国家气象现代化水平的关键标志。在我国数值天气预报的自主创新历程中,以全球/区域同化预报系统(GRAPES)为核心的全面业务体系的建立,是具有里程碑意义的事件,标志着从技术引进到自主创新的重大跨越。本文重点综述了新世纪以来GRAPES发展过程中在核心技术方面取得的原创性成果,主要包括预估-修正的半隐式半拉格朗日时间积分方案、多矩约束有限体积方法、高精度正定保形平流方案、双参数云物理方案、尺度自适应湍流参数化方案、快速辐射传输模式、非静力全球模式的切线和伴随模式、有约束卫星资料偏差订正、FY-4红外高光谱同化算法等方面的自主创新发展。这些突破是基础研究与业务实践紧密结合的成果,全面提升了我国自主研发的数值天气模式的预报性能。 展开更多
关键词 数值天气预报 GRAPES 半隐式半拉格朗日(SISL) 有限体积方法 物理过程参数化 四维变分 卫星资料同化
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数据驱动的船舶动力冷凝器系统容错控制策略研究
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作者 王豪 李献领 +3 位作者 宁哲远 乔新宇 蒋宇辰 罗浩 《热能动力工程》 北大核心 2025年第6期101-109,共9页
随着船舶动力系统智能化和自动化水平的提升,其复杂性和故障率显著增加,对安全性和可靠性提出了更高要求。针对传统容错控制方法依赖精确模型的局限性,提出了一种基于Youla参数化的数据驱动容错控制方法,通过自适应观测器实时辨识冷凝... 随着船舶动力系统智能化和自动化水平的提升,其复杂性和故障率显著增加,对安全性和可靠性提出了更高要求。针对传统容错控制方法依赖精确模型的局限性,提出了一种基于Youla参数化的数据驱动容错控制方法,通过自适应观测器实时辨识冷凝器的系统参数,并利用残差驱动的Youla参数化控制器进行在线参数学习,实现了控制性能的实时优化与容错控制。仿真结果表明:进行容错控制后水位的跟踪误差较没有进行容错控制减小约50%,说明所提方法能够有效进行容错控制并显著提高冷凝器系统的可靠性。 展开更多
关键词 船舶动力冷凝器系统 故障诊断 容错控制 数据驱动 实时优化 YOULA参数化
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基于BIM的跨海桥梁地质模型构建与集成共享研究
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作者 时笑鹏 罗东超 +1 位作者 刘天成 程潜 《工程建设与设计》 2025年第5期131-134,共4页
针对跨海桥梁地质模型与结构体模型融合不足、共享利用难等问题,论文提出了一种基于BIM的地质体和结构体动态建模与集成共享技术,包括以SpringBoot作为主框架的多元数据融合地质数据库搭建,基于Kriging插值的三维地质模型自动构建Revit... 针对跨海桥梁地质模型与结构体模型融合不足、共享利用难等问题,论文提出了一种基于BIM的地质体和结构体动态建模与集成共享技术,包括以SpringBoot作为主框架的多元数据融合地质数据库搭建,基于Kriging插值的三维地质模型自动构建Revit插件研发,基于Dynamo定制化族库的桥梁结构体参数化建模,以Cesium作为三维引擎的模型数据集成共享可视化平台开发。在黄茅海跨海大桥中的应用结果表明该技术能够有效提高跨海桥梁地质模型与结构模型的建立与共享效率。 展开更多
关键词 桥梁 地质 数据融合 BIM 参数化 CESIUM 共享
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基于RDMA的高效拥塞控制方法设计
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作者 王芳慧 黄正峰 +1 位作者 邱麟雅 郭二辉 《合肥工业大学学报(自然科学版)》 北大核心 2025年第10期1344-1351,共8页
文章研究并解决数据中心的远程内存直接读取(remote direct memory access, RDMA)技术的网络拥塞控制问题。针对主流拥塞控制算法数据中心量化拥塞通知(data center quantized congestion notification, DCQCN)的收敛速度慢和缺乏硬件... 文章研究并解决数据中心的远程内存直接读取(remote direct memory access, RDMA)技术的网络拥塞控制问题。针对主流拥塞控制算法数据中心量化拥塞通知(data center quantized congestion notification, DCQCN)的收敛速度慢和缺乏硬件实现方案的不足,提出可参数硬件化的数据中心量化拥塞通知(parameterized DCQCN,DCQCN-p)算法,该算法通过优化拥塞流的速度因子a、g调整速度比例Rc,并通过电路设计减少降速的频次;通过建立算法模型和搭建网络仿真NS-3平台,对比DCQCN-p算法在面临拥塞时单个调度流速度调整的性能以及多个调度流并发情况下的时延和吞吐量。仿真结果表明:在单个流面临拥塞时,DCQCN-p算法的数据传输速率比DCQCN算法的提高了50%;DCQCN-p算法在链路上最小速率为13.28 Gbit/s,相较于DCQCN、TIMELY、数据中心传输控制协议(data center transmission control protocol, DCTCP)算法,分别增长了24%、48%、23%;DCQCN-p算法(方差65%)的带宽分配公平性相较于TIMELY算法(方差216%)和DCTCP算法(方差191%)表现出显著的性能提升。 展开更多
关键词 远程内存直接读取(RDMA) 可参数硬件化的数据中心量化拥塞通知(DCQCN-p)算法 电路设计 多流高效 网络仿真
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基于目标检验条件生成对抗网络的翼型反设计方法
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作者 孟宪超 陶俊 《航空学报》 北大核心 2025年第10期120-134,共15页
基于条件生成对抗网络(CGAN),通过在CGAN后附加多层感知机(MLP)检验器,发展了一种目标检验条件生成对抗网络(TT-CGAN)并将其用于翼型反设计。TT-CGAN可以重点检验设计目标的实现效果,增强了CGAN对于附加条件的检验效果。基于UIUC翼型数... 基于条件生成对抗网络(CGAN),通过在CGAN后附加多层感知机(MLP)检验器,发展了一种目标检验条件生成对抗网络(TT-CGAN)并将其用于翼型反设计。TT-CGAN可以重点检验设计目标的实现效果,增强了CGAN对于附加条件的检验效果。基于UIUC翼型数据库,选取了797个真实翼型,并通过求解基于雷诺平均Navier-Stokes(RANS)方程组计算得到了各翼型对应的气动参数,形成真实翼型数据库;利用类别/形状函数变换(CST)方法对翼型外形进行参数化,将翼型外形从100维几何参数描述为14维CST参数。通过特征级融合方式将升力系数、阻力系数、表面压力分布融合得到多模态气动参数,并与基于升阻力系数的气动参数作对比,分别作为网络的附件条件,进行翼型反设计。结果表明,基于多模态数据TT-CGAN的翼型反设计方法生成结果更为精准,翼型几何外形的平均均方根误差为1.779×10^(-3),平均绝对误差为1.351×10^(-3)。通过求解RANS方程组对生成翼型进行数值模拟验证,结果显示其升力系数的平均相对误差为3.5998%,阻力系数的平均相对误差为3.7239%,生成翼型的升阻力系数均满足设计指标,生成结果较精准。通过比较训练样本与测试样本的升阻比分布,发现升阻比在[20,30)区间上的翼型占总测试集的40%,而升阻比在此区间的训练翼型仅占训练集的16%,即使在训练样本较少的区间,该方法也能实现准确的预测,具有一定泛化性。 展开更多
关键词 翼型反设计 条件生成对抗网络(CGAN) 多模态数据融合 类别/形状函数变换 参数化
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Validation of LAMOST stellar parameters with the PASTEL catalog 被引量:2
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作者 Hua Gao Hua-Wei Zhang +8 位作者 Mao-Sheng Xiang Yang Huang Xiao-Wei Liu A-Li Luo Hao-Tong Zhang Yue Wu Yong Zhang Guang-Wei Li Bing Du 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第12期2204-2212,共9页
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) published its first data release (DR1) in 2013, which is currently the largest dataset of stellar spectra in the world. We combine the PASTEL ... The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) published its first data release (DR1) in 2013, which is currently the largest dataset of stellar spectra in the world. We combine the PASTEL catalog and SIMBAD radial velocities as a testing standard to validate stellar parameters (effec- tive temperature Tefr, surface gravity log g, metallicity [Fe/H] and radial velocity Vr) derived from DR1. Through cross-identification of the DR1 catalogs and the PASTEL catalog, we obtain a preliminary sample of 422 stars. After removal of stellar param- eter measurements from problematic spectra and applying effective temperature con- straints to the sample, we compare the stellar parameters from DR1 with those from PASTEL and SIMBAD to demonstrate that the DR1 results are reliable in restricted ranges of Tefr. We derive standard deviations of 110 K, 0.19 dex and 0.11 dex for Tell, log 9 and [Fe/H] respectively when Teff〈 8000 K, and 4.91 km s-1 for Vr when Teff 〈 10 000 K. Systematic errors are negligible except for those of Vr. In addition, metallicities in DR1 are systematically higher than those in PASTEL, in the range of PASTEL [Fe/H] 〈 -1.5. 展开更多
关键词 stars: fundamental parameters -- astronomical data bases: catalogs --astronomical data bases: surveys
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Implementing a multispecies size-spectrum model in a datapoor ecosystem 被引量:5
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作者 ZHANG Chongliang CHEN Yong +1 位作者 THOMPSON Katherine REN Yiping 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第4期63-73,共11页
Multispecies ecological models have been used for predicting the effects of fishing activity and evaluating the performance of management strategies. Size-spectrum models are one type of physiologically-structured eco... Multispecies ecological models have been used for predicting the effects of fishing activity and evaluating the performance of management strategies. Size-spectrum models are one type of physiologically-structured ecological model that provide a feasible approach to describing fish communities in terms of individual dietary variation and ontogenetic niche shift. Despite the potential of ecological models in improving our understanding of ecosystems, their application is usually limited for data-poor fisheries. As a first step in implementing ecosystem-based fisheries management(EBFM), this study built a size-spectrum model for the fish community in the Haizhou Bay, China. We describe data collection procedures and model parameterization to facilitate the implementation of such size-spectrum models for future studies of data-poor ecosystems. The effects of fishing on the ecosystem were exemplified with a range of fishing effort and were monitored with a set of ecological indicators. Total community biomass, biodiversity index, W-statistic, LFI(Large fish index), Mean W(mean body weight) and Slope(slope of community size spectra) showed a strong non-linear pattern in response to fishing pressure, and largest fishing effort did not generate the most drastic responses in certain scenarios. We emphasize the value and feasibility of developing size-spectrum models to capture ecological dynamics and suggest limitations as well as potential for model improvement. This study aims to promote a wide use of this type of model in support of EBFM. 展开更多
关键词 size-spectrum model trophic interaction data-poor model parameterization Haizhou Bay
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Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST) 被引量:6
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作者 Yue Wu A-Li Luo +10 位作者 Hai-Ning Li Jian-Rong Shi Philippe Prugniel Yan-Chun Liang Yong-Heng Zhao Jian-Nan Zhang Zhong-Rui Bai Peng Wei Wei-Xiang Dong Hao-Tong Zhang Jian-Jun Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2011年第8期924-946,共23页
A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters o... A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares to measure the fundamental parameters of the stars. Adopting the ULySS package, we have tested the effect of different resolutions and signal-to- noise ratios (SNR) on the measurement of the stellar atmospheric parameters (effective temperature Teff, surface gravity log g, and metaUicity [Fe/H]). We show that ULySS is reliable for determining these parameters with medium-resolution spectra (R ~2000). Then, we applied the method to measure the parameters of 771 stars selected in the commissioning database of the Guoshoujing Telescope (LAMOST). The results were compared with the SDSS/SEGUE Stellar Parameter Pipeline (SSPP), and we derived precisions of 167 K, 0.34dex, and 0.16dex for Teff, logg and [Fe/H] respectively. Furthermore, 120 of these stars are selected to construct the primary stellar spectral template library (Version 1.0) of LAMOST, and will be deployed as basic ingredients for the LAMOST automated parametrization pipeline. 展开更多
关键词 astronomical data bases: atlases -- stars: fundamental parameters techniques: spectroscopic -- surveys
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Estimating stellar atmospheric parameters based on Lasso features 被引量:1
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作者 Chuan-Xing Liu Pei-Ai Zhang Yu Lu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第4期423-432,共10页
With the rapid development of large scale sky surveys like the Sloan Digital Sky Survey (SDSS), GAIA and LAMOST (Guoshoujing telescope), stellar spectra can be obtained on an ever-increasing scale. Therefore, it i... With the rapid development of large scale sky surveys like the Sloan Digital Sky Survey (SDSS), GAIA and LAMOST (Guoshoujing telescope), stellar spectra can be obtained on an ever-increasing scale. Therefore, it is necessary to estimate stel- lar atmospheric parameters such as Teff, log g and [Fe/H] automatically to achieve the scientific goals and make full use of the potential value of these observations. Feature selection plays a key role in the automatic measurement of atmospheric parameters. We propose to use the least absolute shrinkage selection operator (Lasso) algorithm to select features from stellar spectra. Feature selection can reduce redundancy in spectra, alleviate the influence of noise, improve calculation speed and enhance the robustness of the estimation system. Based on the extracted features, stellar atmospheric param- eters are estimated by the support vector regression model. Three typical schemes are evaluated on spectral data from both the ELODIE library and SDSS. Experimental results show the potential performance to a certain degree. In addition, results show that our method is stable when applied to different spectra. 展开更多
关键词 methods: data analysis -- stars: fundamental parameters -- techniques:spectroscopic -- surveys
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Estimation of Stellar Atmospheric Parameters from LAMOST DR8 Low-resolution Spectra with 20 ≤ S/N < 30
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作者 Xiangru Li Zhu Wang +4 位作者 Si Zeng Caixiu Liao Bing Du Xiao Kong Haining Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第6期204-214,共11页
The accuracy of the estimated stellar atmospheric parameter evidently decreases with the decreasing of spectral signal-to-noise ratio(S/N)and there are a huge amount of this kind observations,especially in case of S/N... The accuracy of the estimated stellar atmospheric parameter evidently decreases with the decreasing of spectral signal-to-noise ratio(S/N)and there are a huge amount of this kind observations,especially in case of S/N<30.Therefore,it is helpful to improve the parameter estimation performance for these spectra and this work studied the(T_(eff),log g,[Fe/H])estimation problem for LAMOST DR8 low-resolution spectra with 20≤S/N<30.We proposed a data-driven method based on machine learning techniques.First,this scheme detected stellar atmospheric parameter-sensitive features from spectra by the Least Absolute Shrinkage and Selection Operator(LASSO),rejected ineffective data components and irrelevant data.Second,a Multi-layer Perceptron(MLP)method was used to estimate stellar atmospheric parameters from the LASSO features.Finally,the performance of the LASSO-MLP was evaluated by computing and analyzing the consistency between its estimation and the reference from the Apache Point Observatory Galactic Evolution Experiment high-resolution spectra.Experiments show that the Mean Absolute Errors of T_(eff),log g,[Fe/H]are reduced from the LASP(137.6 K,0.195,0.091 dex)to LASSO-MLP(84.32 K,0.137,0.063 dex),which indicate evident improvements on stellar atmospheric parameter estimation.In addition,this work estimated the stellar atmospheric parameters for 1,162,760 lowresolution spectra with 20≤S/N<30 from LAMOST DR8 using LASSO-MLP,and released the estimation catalog,learned model,experimental code,trained model,training data and test data for scientific exploration and algorithm study. 展开更多
关键词 fundamental parameters of stars-astronomy data modeling-algorithms
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A New Economy Forecasting Method Based on Data Barycentre Forecasting Method
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作者 Jilin Zhang Qun Zhang 《Chinese Business Review》 2005年第5期25-28,共4页
A new and useful method of technology economics, parameter estimation method, was presented in light of the stability of gravity center of object in this paper. This method could deal with the fitting and forecasting ... A new and useful method of technology economics, parameter estimation method, was presented in light of the stability of gravity center of object in this paper. This method could deal with the fitting and forecasting of economy volume and could greatly decrease the errors of the fitting and forecasting results. Moreover, the strict hypothetical conditions in least squares method were not necessary in the method presented in this paper, which overcame the shortcomings of least squares method and expanded the application of data barycentre method. Application to the steel consumption volume forecasting was presented in this paper. It was shown that the result of fitting and forecasting was satisfactory. From the comparison between data barycentre forecasting method and least squares method, we could conclude that the fitting and forecasting results using data barycentre method were more stable than those of using least squares regression forecasting method, and the computation of data barycentre forecasting method was simpler than that of least squares method. As a result, the data barycentre method was convenient to use in technical economy. 展开更多
关键词 data barycentre method parameter estimation small sample steel forecasting
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Analysis of Extreme Rainfall Event with Different Microphysics and Parameterization Schemes in WRF Model
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作者 Hiren Satishkumar Lekhadiya Ranjan Kumar Jana 《Positioning》 2018年第1期1-11,共11页
In the present study, the imitation of heavy rainfall event which occurred over Jharkhand during 18 August 2016 was taken as a case study. Weather Research and Forecasting (WRF) model has been utilized for this study.... In the present study, the imitation of heavy rainfall event which occurred over Jharkhand during 18 August 2016 was taken as a case study. Weather Research and Forecasting (WRF) model has been utilized for this study. National Centers for Environmental Prediction (NCEP) analysis data is compared with GSMaP data with different combination of physical parameterization scheme like microphysics (MP) and cumulus parameterization (CP). In the present study, three MP schemes: Kessler scheme, Lin et al. scheme and WRF Single-moment 6-class scheme with combination of three CP schemes: Betts-Miller-Janjic scheme, Multi-scale Kain-Fritsch scheme and New simplified Arakawa-Schubert scheme have been used. The model predicted humidity, temperature and precipitation were compared with the GSMaP product. The model nicely depicted the cloud pattern and recognized the rain event spatially. The obtained result shows that the model overestimates the precipitation for all the schemes. 展开更多
关键词 data ASSIMILATION NWP Model PREDICTION parameterIZATION SCHEMES
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Parameterization based on maximum curvature minimization model
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作者 BAN Jinjin ZHANG Caiming ZHOU Yuanfeng 《Computer Aided Drafting,Design and Manufacturing》 2013年第1期47-52,共6页
Parameterization is one of the key problems in the construction of a curve to interpolate a set of ordered points. We propose a new local parameterization method based on the curvature model in this paper. The new met... Parameterization is one of the key problems in the construction of a curve to interpolate a set of ordered points. We propose a new local parameterization method based on the curvature model in this paper. The new method determines the knots by mi- nimizing the maximum curvature of quadratic curve. When the knots by the new method are used to construct interpolation curve, the constructed curve have good precision. We also give some comparisons of the new method with existing methods, and our method can perform better in interpolation error, and the interpolated curve is more fairing. 展开更多
关键词 ordered data points quadratic curve CURVATURE parameterIZATION
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沙尘气溶胶数值模式与资料同化的研究进展、问题与展望 被引量:1
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作者 范亚伟 杜鹤强 +3 位作者 杨胜飞 颜长珍 刘秀帆 刘欣雷 《地球科学进展》 CAS CSCD 北大核心 2024年第8期813-822,共10页
沙尘气溶胶对气候变化、生态环境和人类生命健康均会产生严重影响,亟待对其进行系统性研究。数值模式是研究沙尘气溶胶的有效工具,能够模拟沙尘的起动、传输、扩散及清除等过程。然而,由于起沙参数化方案的不完整及模式输入场的不确定性... 沙尘气溶胶对气候变化、生态环境和人类生命健康均会产生严重影响,亟待对其进行系统性研究。数值模式是研究沙尘气溶胶的有效工具,能够模拟沙尘的起动、传输、扩散及清除等过程。然而,由于起沙参数化方案的不完整及模式输入场的不确定性,导致数值模式的模拟结果存在较大误差。以此为立足点,论述沙尘气溶胶观测方式、数值模式发展历程、起沙参数化方案进展以及资料同化研究进展。并基于目前的研究现状,分析现阶段利用数值模式进行沙尘气溶胶研究过程中存在的问题,进一步提出未来的发展方向。通过全面回顾沙尘气溶胶数值模拟的研究进程,以期为相关领域研究提供参考和启发。 展开更多
关键词 沙尘气溶胶 数值模式 遥感观测 起沙参数化方案 资料同化
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基于达索平台的雄安东西轴明挖隧道BIM技术研究 被引量:1
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作者 刘超 《铁路计算机应用》 2024年第6期35-39,共5页
为提高雄安东西轴地下明挖隧道设计效率与质量,开展基于达索平台的BIM(Building Information Modeling)设计研究。提出明挖隧道BIM设计流程,对其主体结构、围护结构、防水、接口、钢筋等进行BIM参数化设计。采用Composer软件实现BIM设... 为提高雄安东西轴地下明挖隧道设计效率与质量,开展基于达索平台的BIM(Building Information Modeling)设计研究。提出明挖隧道BIM设计流程,对其主体结构、围护结构、防水、接口、钢筋等进行BIM参数化设计。采用Composer软件实现BIM设计交底,并对成果数据进行集成与共享,实现从设计阶段向施工阶段精度为LOD3.5的BIM成果交付,为后续相关工程的BIM设计应用提供参考。 展开更多
关键词 BIM 地下明挖隧道 参数化设计 设计交底 数据集成与共享
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我国自主研制的全球/区域一体化数值天气预报系统GRAPES的应用与展望 被引量:20
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作者 陈德辉 薛纪善 +4 位作者 沈学顺 孙健 万齐林 金之雁 李兴良 《中国工程科学》 北大核心 2012年第9期46-54,共9页
介绍了中国气象局自主研制的新一代全球与区域一体化数值天气预报系统(GRAPES),着重讨论了该系统的全可压/非静力平衡动力框架,全球模式/区域模式一体化设计,半隐式-半拉格朗日差分方案,标准化、模块化、并行化、模式程序软件体系等核... 介绍了中国气象局自主研制的新一代全球与区域一体化数值天气预报系统(GRAPES),着重讨论了该系统的全可压/非静力平衡动力框架,全球模式/区域模式一体化设计,半隐式-半拉格朗日差分方案,标准化、模块化、并行化、模式程序软件体系等核心技术特点。GRAPES系统已在国家级、区域级气象业务中心,以及一些大学和研究所得到应用,并在不断地完善和发展。 展开更多
关键词 数值预报 天气预报 全球/区域一体化模式 动力框架 资料同化 物理过程参数化
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GRAPES_Meso V4.0主要技术改进和预报效果检验 被引量:100
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作者 黄丽萍 陈德辉 +4 位作者 邓莲堂 徐枝芳 于翡 江源 周非非 《应用气象学报》 CSCD 北大核心 2017年第1期25-37,共13页
针对GRAPES_Meso V3.0存在的降水量偏大、模式运行不稳定、近地面温度预报偏差较大、可同化资料偏少以及分辨率偏低等问题,开展了多方面的改进工作:引入变分质量控制以及探空湿度的偏差订正,实现了GPS/PW资料、FY-2E云导风资料以及无线... 针对GRAPES_Meso V3.0存在的降水量偏大、模式运行不稳定、近地面温度预报偏差较大、可同化资料偏少以及分辨率偏低等问题,开展了多方面的改进工作:引入变分质量控制以及探空湿度的偏差订正,实现了GPS/PW资料、FY-2E云导风资料以及无线电掩星资料的同化应用,提高了模式分辨率,引入四阶水平扩散方案,调整了微物理参数化方案与动力框架的耦合方案,完善了地面辐射能量平衡方程以及优化了后处理雷达组合反射率因子的诊断方案,并集成所有改进成果形成新的业务化GRAPES_Meso V4.0。批量试验结果表明:GRAPES_Meso V4.0降水ETS评分普遍提高,同时预报偏差明显降低,月平均降水更接近实况,且能够较好地刻画雨带细节;2 m温度预报偏差有较为显著的改善,大部分地区24 h预报有1~2℃左右的降低,有些地区有3~5℃的降低;GRAPES_Meso V4.0对高度场、温度场和风场的改进效果比较显著,500 hPa的温度、风速、位势高度场的相关系数均有显著提高,850 hPa的均方根误差也明显降低,整体性能明显高于GRAPES_Meso V3.0。 展开更多
关键词 GRAPES_MesoV4.0 FY-2E资料同化 物理过程参数化 变分质量控制 模式分辨率
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基于机载LiDAR数据的三维树木建模方法 被引量:4
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作者 陈卓 马洪超 邬建伟 《计算机工程》 CAS CSCD 2012年第4期1-3,共3页
提出一种基于机载激光雷达系统LiDAR数据树木可视化建模的方法。利用机载LiDAR数据的特点,结合L-系统分形的思想,对传统的L-系统方法进行随机化、参数化的扩展和改进,由此对数据进行建模。针对LiDAR数据分布空间由内到外的层次特点,采... 提出一种基于机载激光雷达系统LiDAR数据树木可视化建模的方法。利用机载LiDAR数据的特点,结合L-系统分形的思想,对传统的L-系统方法进行随机化、参数化的扩展和改进,由此对数据进行建模。针对LiDAR数据分布空间由内到外的层次特点,采取分步的建模策略,在外层建立从LiDAR数据中提取L-系统参数的方法。实验结果表明,该方法具有较好的建模效果,适用于三维数字城市、虚拟现实以及林业领域。 展开更多
关键词 LiDAR系统 点云数据 参数化L-系统 三维树木模型
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