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   

建筑用地钉桩数据一体化生产技术的应用研究     

秦学秀  赵连柱 《北京测绘》2010,(4):53-56

对建筑用地钉桩数据组织、空间数据存储模型、数据一体化生产技术、系统的设计与实现进行了研究和探讨。提出基于ORACLE关系型数据库和ArcSDE空间数据引擎进行建筑用地钉桩数据管理,建立建筑用地钉桩数据库;建立建筑用地钉桩数据存储模型,基于关系型数据库实现了建筑用地钉桩空间数据和属性数据的统一存储和管理,实现了AutoCAD平台与GIS平台无损数据交换;建立了建筑用地钉桩数据一体化生产管理系统,实现了建筑用地钉桩数据生产一体化、网络化管理及分发服务,具有实用性及推广价值。  相似文献   

上海市集中测绘成果管理系统的建设与维护     

孙纪瑞  周燕 《国土资源信息化》2010,(1):29-34

本文在深入调研上海市集中测绘成果管理系统的基础上,通过对系统的建立与长期维护的总结,简要的介绍了系统实现的功能与系统架构,总结了系统建设过程中的思路与做法。着重阐述了系统在整合测绘处理与成果管理、保持基础数据的现势性方面所取得的成果,总结了系统在建设与使用过程中的优缺点,为其它地区建立或改造测绘成果系统提供借鉴。  相似文献   

The REM Adjoint System and Its 4DVar Data Assimilation Experiments     

WANG Tie  MU Mu 《Acta Meteorologica Sinica》2010,24(6):749-761

The Regional Eta-coordinate Model(REM) has performed well in forecasting heavy rainfalls in China in recent years.A four-dimensional variational assimilation system(4DVar) is developed to improve the forecast skill of the REM.The tangent linear model and adjoint model codes are written according to thecode to coderule,and the establishment of the REM adjoint modeling system is introduced in detail in this paper.The tangent linear and adjoint models of the REM are validated against the observational data,...  相似文献   

Deterministic non-linear wave prediction using probe data     

E. Blondel  F. Bonnefoy  P. Ferrant 《Ocean Engineering》2010,37(10):913-926

The accurate prediction of non-linear sea states represents a great challenge, with a number of applications in oceanography, marine engineering, security of people and marine transportation, etc. In this paper, we report on the development of two efficient deterministic prediction models for 2D irregular wave-fields. These models are based on the exploitation of wave elevation time series given by one or more probes and on the use of two different numerical models for the wave-fields simulation. Two effective data assimilation processes are developed to improve the wave-field estimates obtained from the study of one or several probe signals, so that we obtain proper initial conditions for the forecast. The assimilation schemes have been validated on the reconstruction of model-generated observations and accurate predictions of the corresponding synthetic wave-fields evolution have been obtained.  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   

Time-Expanded Sampling Approach for Ensemble Kalman Filter:Experiment Assimilation of Simulated Soundings          下载免费PDF全文

YANG Yi  GONG Zhongqiang  WANG Jinyan  LIU Xinhua 《Acta Meteorologica Sinica》2011,25(5):558-567

In the Ensemble Kalman Filter (EnKF) data assimilation-prediction system, most of the computation time is spent on the prediction runs of ensemble members. A limited or small ensemble size does reduce the computational cost, but an excessively small ensemble size usually leads to filter divergence, especially when there are model errors. In order to improve the efficiency of the EnKF data assimilation-prediction system and prevent it against filter divergence, a time-expanded sampling approach for EnKF based on the WRF (Weather Research and Forecasting) model is used to assimilate simulated sounding data. The approach samples a series of perturbed state vectors from Nb member prediction runs not only at the analysis time (as the conventional approach does) but also at equally separated time levels (time interval is △t) before and after the analysis time with M times. All the above sampled state vectors are used to construct the ensemble and compute the background covariance for the analysis, so the ensemble size is increased from Nb to Nb+2M￡Nb=(1+2M)×Nb) without increasing the number of prediction runs (it is still Nb). This reduces the computational cost. A series of experiments are conducted to investigate the impact of △t (the time interval of time-expanded sampling) and M (the maximum sampling times) on the analysis. The results show that if △t and M are properly selected, the time-expanded sampling approach achieves the similar effect to that from the conventional approach with an ensemble size of (1+2M)×Nb, but the number of prediction runs is greatly reduced.  相似文献   

Metabolic plasticity of nitrogen assimilation by Porphyra umbilicalis (Linnaeus) Kützing     

Jang K.Kim  George P.Kraemer  Charles Yarish 《中国海洋大学学报(英文版)》2012,11(4):517-526

The physical stresses associated with emersion have long been considered major factors determining the vertical zonation of intertidal seaweeds.We examined Porphyra umbilicalis(Linnaeus) Kützing thalli from the vertical extremes in elevation of an intertidal population(i.e.upper and lower intertidal zones) to determine whether Porphyra thalli acclimate to different vertical elevations on the shore with different patterns of nitrate uptake and nitrate reductase(NR) and glutamine synthetase(GS) activities in response to different degrees of emersion stress.We found that the nitrate uptake and NR recovery in the emersed tissues took longer in lower intertidal sub-population than in upper intertidal sub-population;and GS activity was also significantly affected by emersion and,interestingly,such an activity was enhanced by emersion of thalli from both upper and lower intertidal zones.These results suggested that intra-population variability in post-emersion recovery of physiological functions such as nutrient uptake and NR activity enables local adaptation and contributes to the wide vertical distribution of P.umbilicalis.The high GS activity during periodic emersion stress may be a protective mechanism enabling P.umbilicalis to assimilate nitrogen quickly when it again becomes available,and may also be an evidence of photorespiration during emersion.  相似文献   

The role of the International Maritime Organization in reducing vessel threat to whales: Process,options, action and effectiveness     

Gregory K. Silber  Angelia S.M. Vanderlaan  Ana Tejedor Arceredillo  Lindy Johnson  Christopher T. Taggart  Moira W. Brown  Shannon Bettridge  Ricardo Sagarminaga 《Marine Policy》2012

  相似文献   

A tool for site prioritisation of marine protected areas under data poor conditions     

Lydia C.L. Teh  Louise S.L. TehTony J. Pitcher 《Marine Policy》2012

A challenge of managing data poor fisheries lies in overcoming uncertainties associated with a lack of information on biological and socio-economic conditions. This paper focuses on site prioritisation for marine protected areas, a process that usually imposes moderate to heavy demands on data, time, local expertise, and funds. A fuzzy logic decision support tool for zoning marine areas that is suitable for use in data poor conditions is developed. This tool, the Protected Area Suitability Index (PASI), assesses the suitability of sites for protection based on fishers’ preferences for that site and the site’s conservation value. Only eight input attributes are required to run the PASI, which operates on a series of heuristic rules to estimate a site suitability score that ranges from 0 to 10, where 10 indicates that a site is highly suitable for being protected from fishing. Sensitivity analysis reveals that the PASI is relatively robust, and produces reliable results even as the system is degraded by the loss of data. Eighteen actively fished sites and 11 sites that are closed to fishing are assessed to evaluate how well the PASI is able to distinguish differences between sites. The estimated scores are significantly different (p<0.05), whereby non-fished sites are scored as being more suitable for protection than fished sites. The PASI can be used as a decision support tool to facilitate systematic marine spatial management under data poor conditions, especially in the task of identifying suitable sites for protection.  相似文献