基于多源探测资料的一次广州局地强对流垂直结构分析     

曾琳  张羽  李怀宇  李浩文  高美谭  梁之彦 《热带气象学报》2023,(3):348-360

基于X波段相控阵雷达、S波段双偏振雷达、微波辐射计、风廓线雷达、毫米波云雷达等多源高时空分辨率新型遥感探测资料,对广州后汛期一次局地强对流过程的大气热力、动力及云物理结构变化特征进行了综合分析。结果表明：(1)强对流前8小时前,局地LI、CAPE、SI等对流参数就达到并远远超过了短时强降水的阈值;临近降水大气层结仍向不稳定发展,水汽条件向有利的方向发展;(2)午后局地风形成辐合,上升气流加强,近地层出现弱垂直风切变和低空急流脉动,对强对流的发生发展有一定的指示意义;(3) CINRAD/SA-D雷达CR、DBZM HT、TOPS、VIL等变化与强降水和地面大风的发展有很好的对应关系,同时低层风场观测到阵风锋特征;XPAR-D雷达更高时空分辨率的探测可清晰显示对流发展旺盛阶段的Z_DR弧、K_DP柱、Z_DR柱、V型缺口等特征,为判断雷暴云团的发展程度和预警提供重要信息。  相似文献   

Evaluation of Performance of Polar WRF Model in Simulating Precipitation over Qinghai-Tibet Plateau     

薛建军  肖子牛 《热带气象学报(英文版)》2023,29(4):410-430

Considering the complex topographic forcing and large cryosphere concentration, the present study utilized the polar-optimized WRF model(Polar WRF) to conduct downscaling simulations over the Qinghai-Tibet Plateau(TP) and its surrounding regions. Multi-group experiments with the 10 km horizontal resolution are used to evaluate the modeling of precipitation. Firstly, on the basis of the model ground surface properties upgrade and the optimized Noah-MP, the “betterperforming” configuration suite f...  相似文献   

大气对流初生的研究进展与展望          下载免费PDF全文

姚秀萍  曹晓敏 《大气科学学报》2023,46(6):940-949

大气中的对流初生(Convective Initiation,CI)是强对流天气发生的重要征兆,是强对流天气预报预警的重点所在,近些年越来越被关注。本文回顾了国内外CI的研究进展,主要包括CI的定义、基于雷达数据和卫星数据的CI成熟算法、CI局地时空分布特征、影响CI的主要因子等方面。在此基础上,对CI未来研究作一展望,以期加深对CI的认识,为强对流天气短临预报预警提供参考依据。  相似文献   

江西地区地震动非弹性衰减和场地响应特征研究     

肖孟仁  陈浩  罗丽  查小惠  郭江春 《大地测量与地球动力学》2020,40(3):287-290

以2009年以来江西省地震台网记录到的86个M_L2.5以上地震事件的波形资料为研究对象,通过遗传算法获得介质的品质因子和台站场地响应,并在此基础上计算地震的震源谱参数。结果显示,江西地区Q值与频率f的关系式为Q（f）=323.1f^{0.505 9};大部分台站的场地响应在频率域表现为平坦型,整体上与台站基岩性质相符;近震级M_L与地震矩M₀在单对数坐标下呈线性关系,地震矩与拐角频率呈负相关特征,应力降与地震矩之间没有显著相关性;震源半径与应力降存在显著的双对数关系。  相似文献   

一种估计粗差大小的新方法——先验方差待定参数法     

王杰龙  汪章辉  陈义 《大地测量与地球动力学》2020,40(4):422-424

提出一种利用先验方差信息进行测量数据处理中粗差估计的新方法——先验方差待定参数法。该方法无需进行最小二乘和假设检验,计算简便。从基本原理出发,给出其数学模型,然后通过3个算例,与QUAD法等其他常用的粗差估计方法进行对比,证明该方法的可靠性和实用性。  相似文献   

水源热泵系统中地下水流贯通及其对温度场的影响   总被引：3，自引：0，他引：3  

胡继华  张延军  于子望  吴刚  杨潇瀛  倪福全 《吉林大学学报(地球科学版)》2008,38(6)

利用含水层储能的一般特点,提出流贯通;分析流贯通和热贯通的相互作用、相互影响及对工程实际的意义;并基于地下水水热运移的基本原理,建立地下水流动和热量输运的耦合数值模型。在此基础上对沈阳某场地水源热泵工程的运行进行流场及温度场的数值模拟分析,给出产生流贯通的依据,即利用水力坡度定量的判断流贯通发生与否;当水力坡度变化非常小、可忽略不计时,认为含水层出现流贯通;进而研究抽、灌量对流贯通的影响,发现抽、灌量越大,则出现流贯通时间越短;而大量的抽、灌量更容易发生流贯通,进而会引起热贯通的发生。在实际工程中可降低抽、灌水量,在条件许可的情况下可提高抽、灌井的间距,并可在抽、灌井运行一个周期后调整抽灌井位置,以减少热贯通的发生。  相似文献   

Determination of the parameter pattern and values for a one-dimensional multi-zone unconfined aquifer     

Ya-Chi Chang  Hund-Der Yeh  Yen-Chen Huang 《Hydrogeology Journal》2008,16(2):205-214

In an aquifer, heterogeneity plays an important role in governing groundwater flow. Hence, aquifer characterization should involve both the pattern and values of the hydrogeological parameters. A new analytical solution describing the one-dimensional groundwater flow in a multi-zone unconfined aquifer is presented, and a methodology developed from the analytical solution and a heuristic approach for determining the pattern and values of the aquifer parameters are proposed. The analytical solution demonstrates that the hydraulic head varies spatially and is influenced by aquifer heterogeneity. Simulated annealing, a heuristic approach, is incorporated with the solution to simultaneously identify the pattern and values of the hydraulic conductivity for a horizontal multi-zone unconfined aquifer. This approach may be used to give an approximate result for a two-dimensional problem by dividing the model area into a number of transects along the transverse direction, identifying the parameter values along the longitudinal direction for each transect, and then smoothing the identified results.  相似文献   

Precise temperature monitoring in boreholes: evidence for oscillatory convection? Part II: theory and interpretation     

Vladimir Cermak  Louise Bodri  Jan Safanda 《International Journal of Earth Sciences》2008,97(2):375-384

In the previous part of this work (Cermak, Safanda and Bodri, this volume p.MMM) we have described experimental data and quantified the heterogeneity features of the microtemperature time series. The spectral analysis and the local growth of the second moment technique revealed scaling structure of all observed time series generally similar and suggested the presence of two temperature forming processes. The longer-scale part can be attributed to the heat conduction in compositional and structural heterogeneous solid rocks, further affected by various local conditions. Short-scale temperature oscillations are produced by the intra-hole fluid convection due to inherent instability of water column filling the hole. Here we present how the observational evidence is supported by the results of the computer simulations. The exact modes of intra-hole convection may be different, ranging from quasi-periodic (“quiescent”) state to close of turbulence. As demonstrated by numerical modeling and referred on laboratory experiments, at higher Rayleigh numbers the periodic character of oscillation characteristic for “quiescent” regime is superseded by stochastic features. This so called “oscillatory” convection occurs due to instability within the horizontal boundary layers between the individual convectional cells. In spite of the fact that the basic convective cell motion is maintained and convection is characterized by slow motion, the oscillatory intra-hole flow and corresponding temperature patterns exhibit typical features of turbulence. The idea of boundary layer instability as a source of stochastic temperature fluctuations could explain many distinct features of borehole temperatures that previously cannot be interpreted.  相似文献   

Interactive visualization of 3D mantle convection     

Megan Damon  Masanori C. Kameyama  Michael Knox  David H. Porter  Dave Yuen  Erik O. D. Sevre 《Visual Geosciences》2008,13(1):49-57

The current availability of thousands of processors at many high performance computing centers has made it feasible to carry out, in near real time, interactive visualization of 3D mantle convection temperature fields, using grid configurations having 10–100 million unknowns. We will describe the technical details involved in carrying out this endeavor, using the facilities available at the Laboratory of Computational Science and Engineering (LCSE) at the University of Minnesota. These technical details involve the modification of a parallel mantle convection program, ACuTEMan; the usage of client–server socket based programs to transfer upwards of a terabyte of time series scientific model data using a local network; a rendering system containing multiple nodes; a high resolution PowerWall display, and the interactive visualization software, DSCVR. We have found that working in an interactive visualizastion mode allows for fast and efficient analysis of mantle convection results. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

基于显式统计原理的地质灾害区域预警方法初步研究   总被引：4，自引：0，他引：4       下载免费PDF全文

刘艳辉  刘传正连建发温铭生唐 灿 《中国地质》2008,35(2):344-350

区域预警是提高防灾减灾意识、有效减轻地质灾害造成损失的重要手段。地质灾害显式统计预警理论考虑了地质环境变化与降雨参数等多因素的耦合作用,克服了传统单一临界雨量判据方法的局限。笔者应用地质灾害显式统计预警的基本原理,以中国的东南区为例开展应用研究。选取岩土体类型、地形起伏等12个基础地质环境因素.通过确定性系数模型(CF)综合分析了地质灾害分布与地质环境基础因素的关系.选取地质灾害"潜势度"作为地质环境优劣的指标,并进行了定量计算。选取当日雨量和一个降雨过程的前期累计雨量作为降雨激发因素的指标.采用多元回归的统计分析方法,分析了地质环境因素、降雨激发因素的耦合作用与地质灾害发育情况之间的关系.建立了显式统计的地质灾害预警预报模型。以2006年5月18日台风"珍珠"登陆期间的实况预警情况对模型进行了应用校验。验证了显式统计预警原理及模型方法的可行性和实用性。  相似文献