Three-dimensional numerical simulation of wind-induced barotropic circulation in the Gulf of Patras   总被引：1，自引：0，他引：1  

Nikolaos Th. Fourniotis 《Ocean Engineering》2010,37(4):355-364

The barotropic, wind-induced circulation, which develops in the Gulf of Patras in Western Greece during the winter, is studied using three-dimensional numerical simulations. The simulations are performed using the numerical code MIKE 3 FM (HD). The Gulf's basin is bracketed between two sills, one on the west at the opening with the Ionian Sea and the other on the east at the Straits of Rio-Antirio at the opening with the Gulf of Corinth. The simulations show that the wind-induced flow creates strong currents near the coasts, which determine the sense of rotation of the gyres that develop in the Gulf. Strong currents are also created at the Rio-Antirio Straits. The wind-induced, barotropic currents do not seem to contribute to the direct replenishment of bottom waters, which recirculate between the two sills. Depending on the wind-speed forcing of the flow, the residence time of the waters in the Gulf of Patras is estimated to range from one week to one month.  相似文献   

Reconstruction of eddies by assimilating satellite altimeter data into Princeton Ocean Model   总被引：2，自引：1，他引：1  

YIN Xunqiang  QIAO Fangli  XIA Changshui  L&#; Xin''gang  YANG Yongzeng 《海洋学报(英文版)》2010,29(1):1-11

An optimal interpolation assimilation model for satellite altimetry data is developed based on Princeton Ocean Model (POM), which is applied in a quasi-global domain, by the method of isotropic correlation between sea level anomaly (SLA) and sea temperature anomaly. The perfor- mance of this assimilation model is validated by the modeled results of SLA and the current patterns. Comparisons between modeling and satellite data show that both the magnitudes and distribution patterns of the simulated SLA are improved by assimilation. The most signiˉcant improvement is that meso-scale systems, e.g., eddies, are well reconstructed. The evolution of an eddy located in the northwest Paciˉc Ocean is traced by using the assimilation model. Model results show that during three months the eddy migrated southwestward for about 6 degrees before merging into the Kuroshio. The three dimensional structure of this eddy on 12 August 2001 is further analyzed. The strength of this warm, cyclonic eddy decreases with the increase of depth. The eddy shows di?erent horizontal patterns at di?erent layers, and the SLA and temperature ˉelds agree with each other well. This study suggests that this kind of data assimilation is economic and reliable for eddy reconstruction, and can be used as a promising technique in further studies of ocean eddies as well as other ˉne circulation structures.  相似文献   

Application of FY-2C Cloud Drift Winds in a Mesoscale Numerical Model     

LI Huahong  WANG Man  XUE Jishan  QI Minghui 《Acta Meteorologica Sinica》2010,24(6):740-748

Statistical tests and error analysis of cloud drift winds(CDWs) from the FY-2C satellite were made by using radiosonde observations.According to the error characteristics of the CDW,a bias correction using the thermal wind theory was applied in the data quality control.The CDW data were then assimilated into the GRAPES-meso model via the GRAPES-3DVar.A torrential rain event that occurred in northwestern China during 1-2 July 2005 was simulated.The results indicate that the CDW data were mainly distribute...  相似文献   

Book review of ENCYCLOPEDIA OF NONLINEAR SCIENCE,edited by Alwyn Scott,Routledge, Taylor and Francis Group, 2005, VII +1053 pp., 135, $225 hardback (ISBN 1-57958-385-7).     

Edgar Knobloch 《地球物理与天体物理流体动力学》2013,107(6):535-536

We present three-dimensional (3D) solutions of the magnetohydrostatic equations in the co-rotating frame of reference outside a magnetized rigidly rotating cylinder. We make no symmetry assumption for the magnetic field, but to be able to make analytical progress we neglect outflows and specify a particular form for the current density. The magnetohydrostatic equations can then be reduced to a single linear partial differential equation for a pseudo-potential U, from which the magnetic field can be calculated by differentiation. The equation for U can be solved by standard methods. The solutions can also be used to determine the plasma pressure, density and temperature as functions of all three spatial coordinates. Despite the obvious limitations of this approach, it can, for example, be used as a simple tool to create 3D models for the closed field line regions of rotating magnetospheres without rotational symmetry.  相似文献   

Integration of remote sensing data into hydrological models for reservoir management     

C. LOUMAGNE  M. NORMAND  M. RIFFARD  A. WEISSE  A. QUESNEY  S. LE HÉGARAT-MASCLE 《水文科学杂志》2013,58(1):89-102

Abstract

The purpose of this paper is to present the methodology set up to derive catchment soil moisture from Earth Observation (EO) data using microwave spaceborne Synthetic Aperture Radar (SAR) images from ERS satellites and to study the improvements brought about by an assimilation of this information into hydrological models. The methodology used to derive EO data is based on the appropriate selection of land cover types for which the radar signal is mainly sensitive to soil moisture variations. Then a hydrological model is chosen, which can take advantage of the new information brought by remote sensing. The assimilation of soil moisture deduced from EO data into hydrological models is based principally on model parameter updating. The main assumption of this method is that the better the model simulates the current hydrological system, the better the following forecast will be. Another methodology used is a sequential one based on Kalman filtering. These methods have been put forward for use in the European AIMWATER project on the Seine catchment upstream of Paris (France) where dams are operated to alleviate floods in the Paris area.  相似文献   

国家气象中心数值预报业务的进展   总被引：1，自引：0，他引：1  

裘国庆 《气象》1994,20(12):27-34

在最近的１５年中，国家气象中心的数值预报业务高速度发展，预报模式从北半球模式发展为全球谱模式，并配套建立了资料同化系统和用于降水预报的有限区预报模式，暴雨和台风预报模式正在研制中。目前数值预报时效已延至７天，Ｔ６３９３丙上时的预报水平已优于的数值预报产品的应用技术在不断改进，最高（低）气温下两天ＭＯＳ预报精度已接近预报员制作的综合预报结果。  相似文献   

Uptake of macroelements by the helophytePhalaris arundinacea L.     

Jean Paul Dubois 《Aquatic Sciences - Research Across Boundaries》1994,56(1):70-79

Helophytes are often incorporated into biological wastewater treatment plants. In favourable situations, they can take up large amounts of nutrients. One helophyte, the reed canarygrass (Phalaris arundinacea L.), is fast growing when supplied with sufficient light and nutrients. Experiments were carried out under natural climatic conditions in small plastic tanks filled with sand with regular additions of a balanced and concentrated nutrient solution. In the growing season (May–October), plant production reached 10.5 kg m^–2 of dry biomass, of which 66% was in the aerial parts. Maximum nutrient uptake capacity was reached just after flowering and before senescence (beginning of October): 49% N, 34% P, 52% K and 34% Mg of the input was fixed in the aerial parts, which are easily harvestable. The corresponding values for the below ground parts were 12%, 10%, 11% and 11% respectively. Excretion of K and Mg has been observed when nutrients are translocated to the storage organs.  相似文献   

唐山滦县震区的三维地震透射研究──中、上地壳速度层析成像   总被引：10，自引：4，他引：10       下载免费PDF全文

张先康  杨玉春 《地球物理学报》1994,37(6):759-766,T002

利用布设在唐山滦县震区３０ｋｍ×４０ｋｍ范围内的由８８台数字和模拟地震仪组成的临时台阵，接收来自不同方向６个炮点激发产生的莫霍界面反射波走时，重建了台阵下１-９ｋｍ深度的Ｐ，Ｓ波速度和Ｖ_ｐ／Ｖ_ｓ图像．结果表明。中、上地壳结构存在明显的横向不均匀性．北北东走向的滦县-卢龙断裂自地表向下至少延伸到８ｋｍ深度处，并向北西方向倾斜．中、上地壳存在着近东西向的低速异常条带．这两组构造控制着该区的地震活动．  相似文献   

位于导电介质中三维导体的电磁响应          下载免费PDF全文

靳职理  许洪海 《地球物理学报》1989,32(4):423-432

本文给出一种用积分方程法配合有限差分法计算位于导电介质中三维导体的电磁响应的新途径,在二层大地条件下给出了具体计算方法和结果。详细讨论了围岩介质的导电性对导体异常的影响。这对于开展低阻覆盖层地区的电磁法工作具有一定的指导意义。  相似文献   

自组织人工神经网络在地震综合预报中的应用     

蔡煜东  杨兵  孙虹 《内陆地震》1995,9(1):49-53

运用三维Ｔ·ｋｏｈｏｎｅｎ自组织人工神经网络进行地震综合预报，以云南多震区─滇西南地震区为例进行实际判别计算，预测成功率达１００％。结果表明．神经网络方法性能较好，可望成为进行地震实际预报的一种有效的辅助手段。  相似文献