不同采样率下四分量钻孔应变观测同震变化特征     

唐磊  邱泽华  樊俊屹  罗自浩 《大地测量与地球动力学》2022,42(11):1196-1201

利用湟源台四分量钻孔应变观测的分钟值、1 sps、10 sps和100 sps四种不同采样率的观测数据,通过自检分析、同震应变阶分析和频谱分析等方法研究青海玛多M7.4地震同震变化特征。研究结果表明,分钟采样记录的地震波信息缺失严重,用分钟采样数据进行地震波初动、同震变化幅度等研究将会得到信度较低的结论;采样率越高,记录应变地震波信息的能力越强,但100 sps采样和10 sps采样结果相差不大,10 sps采样已能记录到比较全面的应变地震波信息;同震应变阶的变化性质和变化幅度与采样率无关;未来布设四分量钻孔应变仪时,建议应将采样率至少提高至1 sps。  相似文献   

Numerical Simulation and Analysis of Storm Surges Under Different Extreme Weather Event and Typhoon Experiments in the South Yellow Sea     

ZHANG Mingzong  ZHOU Chunyan  ZHANG Jisheng  ZHANG Xinzhou  TANG Zihao 《中国海洋大学学报(英文版)》2022,21(1):1-14

In this study,a coupled tide-surge-wave model was developed and applied to the South Yellow Sea.The coupled model simulated the evolution of storm surges and waves caused by extreme weather events,such as tropical cyclones,cold waves,extratropical cyclones coupled with a cold wave,and tropical cyclones coupled with a cold wave.The modeled surge level and significant wave height matched the measured data well.Simulation results of the typhoon with different intensities revealed that the radius to the maximum wind speed of a typhoon with 1.5 times wind speed decreased,and its influence range was farther away from the Jiangsu coastal region;moreover,the impact on surge levels was weakened.Thereafter,eight hypothetical typhoons based on Typhoon Chan-hom were designed to investigate the effects of varying typhoon tracks on the extreme value and spatial distribution of storm surges in the offshore area of Jiangsu Province.The typhoon along path 2 mainly affected the Rudong coast,and the topography of the Rudong coast was conducive to the increase in surge level.Therefore,the typhoon along path 2 induced the largest surge level,which reached up to 2.91 m in the radial sand ridge area.The maximum surge levels in the Haizhou Bay area and the middle straight coastline area reached up to 2.37 and 2.08 m,respectively.In terms of typhoons active in offshore areas,the radial sand ridge area was most likely to be threatened by typhoon-induced storm surges.  相似文献   

用基于Givens变换的QR分解计算类GPS广播星历参数   总被引：5，自引：0，他引：5  

崔先强  唐颖哲  姬剑锋  李舒侗 《测绘工程》2006,15(4):5-8

分析研究类GPS广播星历参数拟合算法的必要性,来介绍可用于解最小二乘问题的Givens变换,讨论使用Givens变换计算MEO和小倾角GEO卫星的类GPS广播星历参数的适用性,并用模拟数据进行验证。  相似文献   

抗差估计中几种选权迭代法常数选取的探讨   总被引：9，自引：0，他引：9  

李浩军  唐诗华  黄杰 《测绘科学》2006,31(6):70-71,76

常规抗差估计中采用选权迭代法时常数的取值是否合理直接关系到平差过程能否顺利进行和平差结果的优劣,本文通过对目前几种选权迭代法中常数的选取进行研究;得出:常数按K1=m ax(|(v1-l1)|)、C=m ax(|(vi-li)|)取值时,能有效解决常规取值方法(K1=3.0~8.0或K1=3.0~6.0,C=8)在粗差较大时出现秩亏、法方程系数矩阵奇异的现象,导致平差不能进行或者平差结果出现严重扭曲的问题,同时本文论述了在确保有解的情况下得到最优解的处理方法。  相似文献   

版本差量式时空数据模型研究   总被引：4，自引：0，他引：4  

汪汇兵  唐新明  洪志刚 《测绘科学》2006,31(5):131-133,136

时空数据模型是时态地理信息系统的关键和核心。本文在分析国内外已有研究成果的基础上,结合国家基础测绘项目,提出了“版本-差量”式时空数据模型,采用“版本管理-动态关联”以及“动态分级索引”技术实现时态地理数据的存储管理和查询检索。该模型能有效降低数据冗余,提高数据访问效率。  相似文献   

国家基础航空摄影成果数据库的设计与建立     

王瑞幺  严荣华  朱武  廖安平  汤海 《测绘通报》2006,(11):35-37,61

通过对国家基础航空摄影成果资料进行分析,从国家基础航空摄影成果资料的集成管理、安全存储、档案管理等方面的需求出发,提出国家基础航空摄影成果数据库建库的数据组织方式和数据存储模式,并通过设计建立国家基础航空摄影成果数据库管理系统,实现国家基础航空摄影成果资料海量、复杂、多样数据的存储管理和分发服务。  相似文献   

Comprehensive Marine Observing Experiment Based on High-Altitude Large Unmanned Aerial Vehicle(South China Sea Experiment2020 of the “Petrel Project”)     

Xuefen ZHANG  Liangxu LI  Rongkang YANG  Ran GUO  Xia SUN  Jianping LUO  Hongbin CHEN  Daxin LIU  Kebing TANG  Wenwu PENG  Xiaodong HAN  Qiyun GUO  Xiaoxia LI  Xikun FEI 《大气科学进展》2021,38(4):531-537

In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models.  相似文献   

A Positivity-preserving Conservative Semi-Lagrangian Multi-moment Global Transport Model on the Cubed Sphere     

Jie TANG  Chungang CHEN  Xueshun SHEN  Feng XIAO  Xingliang LI 《大气科学进展》2021,38(9):1460-1473

A positivity-preserving conservative semi-Lagrangian transport model by multi-moment finite volume method has been developed on the cubed-sphere grid. Two kinds of moments(i.e., point values(PV moment) at cell interfaces and volume integrated average(VIA moment) value) are defined within a single cell. The PV moment is updated by a conventional semi-Lagrangian method, while the VIA moment is cast by the flux form formulation to assure the exact numerical conservation. Different from the spatial approximation used in the CSL2(conservative semi-Lagrangian scheme with second order polynomial function) scheme, a monotonic rational function which can effectively remove non-physical oscillations is reconstructed within a single cell by the PV moments and VIA moment. To achieve exactly positive-definite preserving, two kinds of corrections are made on the original conservative semi-Lagrangian with rational function(CSLR)scheme. The resulting scheme is inherently conservative, non-negative, and allows a Courant number larger than one.Moreover, the spatial reconstruction can be performed within a single cell, which is very efficient and economical for practical implementation. In addition, a dimension-splitting approach coupled with multi-moment finite volume scheme is adopted on cubed-sphere geometry, which benefitsthe implementation of the 1 D CSLR solver with large Courant number.The proposed model is evaluated by several widely used benchmark tests on cubed-sphere geometry. Numerical results show that the proposed transport model can effectively remove nonphysical oscillations and preserve the numerical nonnegativity, and it has the potential to transport the tracers accurately in a real atmospheric model.  相似文献   

2015—2019年甘肃平凉地区夏季短时强降水时空分布及天气形势特征     

薛啟  唐亚平  王丽娜  郭海峰  赵慧  马鹏程 《气象与环境学报》2022,38(1):57-64

选取了甘肃平凉地区2015-2019年6-8月发生的27次短时强降水事件。利用自动站逐小时降水资料和高空探测资料,按照短时强降水阈值分类统计法和常规天气分析方法对甘肃平凉地区夏季短时强降水时空分布、影响天气系统及大气环境背景进行了统计分析。结果表明：6月短时强降水频次少,强降水高发区为六盘山山区;7月频次明显增多,活跃地区为静宁、崇信、泾川一带;8月频次及强度达到峰值,密集区为平凉北部的崆峒山区、崇信南部河谷地带。6月短时强降水日变化呈现单峰型特征,以午后居多,1 h降水量在20-30 mm段发生频次最高,占6月频次的80%以上;7月和8月日变化呈多峰型结构,夜间短时强降水频次增多,1 h降水量大于30 mm的频次显著增加,约占7月和8月总频次的40%。分析总结了平凉地区短时强降水天气类型,即高空低槽类、副热带高压类、西北气流类。另外,对表征动力、水汽、不稳定条件的环境参数统计分析,结果显示K指数、CAPE、T₈₅₀-T₅₀₀、Q₈₅₀、θ_se-850等物理量平均特征值对平凉地区强降水预报有较好的指示意义。  相似文献   

2021年夏季中国气候异常特征及主要气象灾害   总被引：1，自引：0，他引：1  

唐懿  蔡雯悦  翟建青  王素萍  刘远  陈逸骁  高歌  王国复 《干旱气象》2022,40(2):179-186

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