基于观测约束的地基犌犘犁三维水汽层析技术研究   总被引：1，自引：0，他引：1  

万蓉  郑国光  于胜杰  付志康 《气象学报》2013,71(2):318-331

全球定位系统(GPS)卫星信号穿过大气层时发生的偏折和延迟,可以用来反演信号传播路径上的大气水汽总量。为获取区域高精度的大气水汽三维分布,借助分布密集的地基GPS观测网及其斜路径水汽观测,建立新的观测约束层析模型,提出以高斯函数为水平约束,区域逐月多年探空观测为垂直约束,即以平均量为先验值,以标准偏差为权重矩阵的新方法;并在层析算法中引入地面观测,以提高整体尤其是低层反演精度。三维水汽层析网格模型基于长江中游鄂东区域的22站地基GPS加密网搭建,实时解算系统可逐时输出三维水汽产品。三维湿折射度和水汽密度可以分别由斜路径的湿延迟总量和水汽总量观测反演获得。以2010年开展的汛期联合加密探空观测为参照,对三维层析的总体反演精度、低层反演精度、层析区域中心与边缘反演精度进行了对比和分析。结果显示:整体样本检验三维水汽密度平均偏差为-0.63 g/m~3,标准偏差为1.22 g/m~3,与探空相关系数为0.98;水汽密度与探空资料的相关比湿折射度与探空资料的相关好;对于不同层析区域,中心区域观测元数量较为丰富,使得位于中心的层析精度好于整体和边缘;加入低层观测的层析结果与探空的相关比未加低层观测时的好,低层观测的加入提高了层析与探空的相关,减小了低层层析标准差、区域中心和2 km以上层析的均差,有效提高了反演精度;低层观测的加入对整体标准差的影响,可能与加剧观测方程中长度矩阵元素间的量级差异有关。  相似文献   

影响云和降水的动力、热力与微物理因素的研究概述   总被引：5，自引：0，他引：5  

廖菲  洪延超  郑国光 《气象》2006,32(11):3-11

由于云和降水的发生、发展是大气动力、热力过程与云中微物理过程相结合的产物，因而受到这些过程的共同制约和影响。为了更加详细地了解影响云和降水的动力、热力与微物理因素，分别从3个方面概要性地进行了阐述。（1）动力作用对云和降水发展的影响：主要讨论了风切变、天气系统抬升、地形动力作用和湍流的作用等因素的作用。（2）影响云和降水发展的热力因素：分别对热力扰动、潜热的作用、辐射作用等做了分析。（3）微物理过程对云和降水发展的影响：主要从微物理过程对动力热力过程的影响、带电过程对云降水粒子的影响、以及微物理过程对云降水影响的相对重要性等方面进行讨论。并在最后扼要地指出了在研究云和降水问题时，将动力、热力过程和微物理过程结合起来研究的必要性。  相似文献   

Mesoscale Structure of Rainstorm Retrieved from Dual-Doppler Radar Observations Using the 4DVAR Assimilation Technique   总被引：1，自引：0，他引：1       下载免费PDF全文

XU Xiaoyong  LIU Liping  ZHENG Guoguang 《Acta Meteorologica Sinica》2006,20(3):334-351

The four-dimensional variational (4DVAR) data assimilation method was applied to dual-Doppler radar data about two Meiyu rainstorms observed during CHeRES (China Heavy Rain Experiment and Study). The purpose of this study is to examine the performance of the 4DVAR technique in retrieving rainstorm mesoscale structure and to reveal the feature of rainstorm mesoscale structure. Results demonstrated that the 4DVAR assimilation method was able to retrieve the detailed structure of wind, thermodynamics, and microphysics fields from dual-Doppler radar observations. The retrieved wind fields agreed with the dual-Doppler synthesized winds and were accurate. The distributions of the retrieved perturbation pressure, perturbation temperature, and microphysics fields were also reasonable through the examination of their physical consistency. Both of the two heavy rainfalls were caused by merging cloud processes. The wind shear and convergence lines at middle and lower levels were their primary dynamical characteristics. The convective system was often related to low-level convergence and upper-level divergence coupled with up-drafts. During its mature stage, the convective system was characterized by low pressure at lower level and high pressure at upper level, associated with warmer at middle level and colder at lower and upper levels than the environment. However, a region of cooling and high pressure occurred in the lower and middle levels compared to warming and low pressure in the upper level during its dissipating stage. The water vapor, cloud water, and rainwater corresponded to the convergence, the updraft and the intensive reflectivity, respectively.  相似文献   

Numerical Simulations of the Physical Process for Hailstone Growth     

FANG Wen  ZHENG Guoguang  HU Zhijin 《Acta Meteorologica Sinica》2005,19(1):93-101

1. IntroductionTheoretical and experimental studies on the phys-ical processes of hail growth (Schumann, 1938; Lud-lan, 1958; List, 1963) showed that its growth rate andstructural characteristics depend on the heat and masstransfers; its dynamic characteristics determine hail-stone's movement and stay in clouds and damage doneto ground bodies, actually controlling the growth in-side clouds. As we know, the heat transfers affectsdirectly hailstone's wet growth, melting and evapo-ration. In the…  相似文献   

东秦岭“武关岩群”斜长角闪岩Sm-Nd同位素年龄及其地质意义     

裴先治  李厚民  李国光  张维吉  王全庆  李志昌 《地质通报》1997,(1)

东秦岭商丹断裂带南侧的“武关岩群”是从原泥盆系刘岭群北侧解体出来的变质沉积—火山岩系。已获得该构造岩石地层单位中斜长角闪岩（变质基性火山岩）ＳｍＮｄ同位素等时线年龄为（１３８２±３０）Ｍａ，钕同位素初始比值ＩＮｄ＝０．５１１１８６±１（２σ），εＮｄ（Ｔ）＝＋６．５１。表明武关岩群”变质岩系主体形成时代为中元古代，这一结果必将导致人们重新认识秦岭造山带的构造发展演化过程  相似文献   

东秦岭武关岩群的组成特征及其大地构造意义   总被引：1，自引：0，他引：1  

裴先治  李厚民  李国光 《地球科学与环境学报》1998,20(1):4

东秦岭商丹地区的武关岩群是从原刘岭群北部分解出来的新的构造岩石地层单位,已获得其中变质基性火山岩Ｓｍ－Ｎｄ同位素年龄为（１３８２±３０）Ｍａ,原岩建造主体为碎屑沉积岩－碳酸盐岩－基性火山岩组合。变质基性火山岩及碎屑沉积岩的岩石地球化学特征表明,他们分别属于大陆板内拉斑玄武岩和大陆岛弧－活动陆缘型杂砂岩,因而武关岩群主体形成于中元古代晚期秦岭造山带拉张裂谷体制构造环境,于晋宁期（１０００～８００Ｍａ）的俯冲碰撞造山过程中拼贴于商丹构造带南侧。  相似文献   

数值模拟方法在岩溶大泉泉口集中供水评价中的应用研究     

任增平  迟宝明  余国光  阎俊萍 《吉林大学学报(地球科学版)》1998,(4)

在地下水流数值模拟中,一般将泉水概化为已知的汇项来处理,而预测水源地的开采对泉水的干扰影响时,泉流量是待求的。利用数学模型的调节反馈功能,通过将延河、下河泉区水位近似恒定作为约束条件,逐时段反复调试泉水流量进行水位拟合,较好地解决了延河泉域人工开采干扰泉水溢流量预报这一难题。  相似文献   

世界著名水下开沟机械设计施工公司与机型介绍   总被引：1，自引：0，他引：1  

张国光 《海洋技术学报》1996,15(2):55-64

本文重点介绍了１５家世界著名的水下开沟机械研究、开发及施工应用公司的基本情况，主要机型的结构特征、技术参数和最新进展。笔者认为：引进先进、成熟的水下开沟机械，或与著名的专业公司联合设计开发，对于中小型海洋工程公司而言，不失为一条投资少、起点高、见效快的好的途径。  相似文献   

Fault movements and stress accumulation before the 1976 Tangshan earthquake in North China   总被引：1，自引：0，他引：1  

Zhao Guoguang  Huang Peiyu 《Journal of Structural Geology》1981,3(4):393-400

This paper analyses geodetic data including the results of short baseline and short levelling surveys across active faults, and of relevellings over a wide area collected at Tangshan and in its vicinity during the several years before the 1976 Tangshan earthquake of magnitude 7.8. Using a theoretical model for slip on a fault plane with an arbitrary dip in a viscoelastic half-space, the parameters of the aseismic fault slip prior to the shock are obtained, and the stress changes caused in the area of Tangshan by such slip are estimated. The results are comparable with the seismic activity and the changes in time and space of the b-value in the relation N = exp(a - bM) observed in the same period. It is demonstrated that during 1968–1975 the Cangdong fault, the main NNE-trending active fault in the southwest of the seismic region, had gradually started aseismic right-lateral strike-slip and that the occurrence of the Tangshan earthquake was related to the stress field produced by the slip. Finally, two sequences of periodic earthquake migration that took place in North China during 1966–1976 are discussed in connection with the Tangshan earthquake.  相似文献   

一种分解地球化学数据混合分布的稳健统计方法     

陈国光  阮天健 《地球科学》1992,17(4):465-470

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