Relative performance of future altimeter systems and tide gauges in constraining a model of North Sea high-frequency barotropic dynamics     

Baptiste Mourre  Pierre De Mey  Yves Ménard  Florent Lyard  Christian Le Provost 《Ocean Dynamics》2006,56(5-6):473-486

We evaluate in this paper the ability of several altimeter systems, considered separately as well as together with tide gauges, to control the time evolution of a barotropic model of the North Sea shelf. This evaluation is performed in the framework of the particular model errors due to uncertainties in bathymetry. An Ensemble Kalman Filter (EnKF) data assimilation approach is adopted, and observing-systems simulation experiments (OSSEs) are carried out using ensemble spread statistics. The skill criterion for the comparison of observing networks is, therefore, not based on the misfit between two simulations, as done in classic twin experiments, but on the reduction of ensemble variance occurring as a consequence of the assimilation. Future altimeter systems, such as the Wide Swath Ocean Altimeter (WSOA) and satellite constellations, are considered in this work. A single WSOA exhibits, for instance, similar performance as two-nadir satellites in terms of sea-level correction, and is better than three satellites in terms of model velocity control. Generally speaking, the temporal resolution of observations is shown to be of major importance for controlling the model error in these experiments. This result is clearly related to the focus adopted in this study on the specific high-frequency response of the ocean to meteorological forcing. Altimeter systems lack adequate temporal sampling for properly correcting the major part of model error in this context, whereas tide gauges, which provide a much finer time resolution, lead to better global statistical performance. When looking into further detail, tide gauges and altimetry are demonstrated to exhibit an interesting complementary character over the whole shelf, as tide gauge networks make it possible to properly control model error in a ∼100-km coastal band, while high-resolution altimeter systems are more efficient farther from the coast.  相似文献   

基于卡尔曼滤波的信息融合技术在区域化探异常综合评价中的应用探索   总被引：5，自引：0，他引：5  

郭科  陈聆  唐菊兴  魏友华  彭继兵 《地学前缘》2006,13(5):533-536

在地球化学综合异常评价中,首次使用基于卡尔曼滤波的信息融合技术,对具有复杂地质地貌特征的西藏恒星错测区1∶50000水系沉积物测量的异常数据进行综合异常评价解释,该方法是把测区的地球化学元素视为多个传感器,将各地球化学元素的异常数据利用集中式多传感器卡尔曼滤波算法进行信息融合,绘制了综合异常图,并对恒星错测区进行了综合异常评价。综合异常图显示结果表明,该方法不同于传统意义上对各单元素异常的机械叠合,基本上消除了无成矿意义上的假异常,而且使致矿异常更为集中,异常形态表现为圈闭良好的椭圆状或圆状,综合异常形态清晰,得到的异常与测区内发现和评价的矿产基本一致。这表明采用基于卡尔曼滤波的信息融合技术处理综合异常的方法较传统方法更行之有效。  相似文献   

动态定位有色噪声影响函数--以一阶AR模型为例   总被引：17，自引：3，他引：17  

杨元喜  崔先强 《测绘学报》2003,32(1):6-10

动态定位的精度和可靠性除受观测偶然误差和系统误差的影响外，还受时间相依的有色噪声的影响。任何基于高斯白噪声假设而忽略实际有色噪声影响的数据处理理论和方法均不能保证估计结果的实际可靠性。基于动态数据处理的2种主要方法，即序贯平差法和Kalman滤波法，将有色噪声分为有色观测噪声和有色状态噪声分别进行讨论。结果表明，有色噪声对状态参数的影响是明显的，由影响函数所计算的结果是可靠的。  相似文献   

A numerical inversion scheme for geoelectrical soundings     

Olu Agunloye 《Pure and Applied Geophysics》1981,119(5):1003-1023

A simple numerical inversion scheme for estimatingn-layer model parameters from observed geoelectrical resistivity data can be used in either the space or wavenumber domain. The technique utilizes Madden's Transmission Line Analogy to compute the resistivity transforms and linear filter theory to accomplish the excursions between the space and wavenumber domains. The inversion is effected by an iterative refinement scheme employing the stochastic inverse which is approximate to the generalized inverse. No singular decomposition analysis is required and the scheme is stable under ill conditions. The inversion scheme not only gives the desired estimates; it exposes redundant parameters and irrelevant data and is easily programmed on a desk-top mini computer. Examples of inverse modeling with hypothetical and field data are discussed.  相似文献   

Photochemical Degradation of Hydrophilic Xenobiotics in the UV/H2O2-process. Influence of Humic Matter on the Degradation Rate of 2-Amino-1-naphthalenesulfonate and Ethylenediaminetetraacetate     

M. Srensen  U. Tanner  G. Sagawe  F. H. Frimmel 《洁净——土壤、空气、水》1996,24(3):132-136

Photochemical oxidation methods are able to eliminate hydrophilic xenobiotics with a high efficiency. In waters with high DOC values caused by humic substances (HS) which are able to absorb UV light, problems can result. The degradation rates of the micropollutants using irradiation wavelengths in the range between λ = 200 nm to λ = 260 nm are significantly influenced by HS. This is mainly caused by the high absorption of the HS at shorter wavelength. In the presence of HS, the photolytic degradation of EDTA and FeEDTA was slowed down by an inner filter effect. A similar tendency could be seen for the photolytic degradation of 2-amino-1-naphthalenesulfonate where additional effects to the inner filter effect were also operating. In the UV/H₂O₂-process, the decrease of the degradation rate could be assigned to the ability of the HS to scavenge HO radicals.  相似文献   

Membrane effects during filtering investigation of membrane effects during filtering of natural surface waters in Missouri     

Rosanna Saindon  T. M. Whitworth 《Aquatic Geochemistry》2006,12(4):365-374

Previous work has demonstrated that suspended clay accumulating on filter paper can act as a membrane and affect chemical concentrations in the filtered water. For this reason, we looked at the possibility of membrane effects altering water chemistry during filtering for Missouri Rivers. Membrane effects during filtering could cause an initial decrease in sample concentrations as the filter cake began acting as a membrane, with a corresponding increase of concentration as the concentration polarization layer was formed behind the filter cake. Samples from five Missouri rivers were tested: the Mississippi River at St. Louis, the Missouri River at Kansas City, the Gasconade River at Jerome, the Osage River at the junction of Highway 63 and 50, and the Meramec River one mile downstream from springs. Three 1-l samples were filtered from each river using a 0.45 m filter. An unfiltered sample from each river underwent dialysis to determine the actual ion concentrations of the overall sample. None of the filtered samples demonstrated a statistically significant alteration of water chemistry using current filtering techniques in this preliminary study, suggesting that membrane effects due to accumulation of clay particles on filter paper may not be a common problem in Missouri and similar regions.  相似文献   

福州乌鸦咀泉水电导率幅频谱分析初探     

林国元  张清秀  毛华锋  张义德 《福建地震》2005,(Z1)

地震观测数据受各种周期性因素影响,其动态曲线表现为周期性变化特征,是大小不同的周期和非周期因素相互作用的结果。利用MATLAB工具包,编程幅频分析和滤波程序,以福州乌鸦咀泉水电导率的模拟观测数据为例,对其幅频谱特征和震例进行初步探讨。  相似文献   

平顶山地区日最高气温预报     

樊白杰  李戈 《河南气象》2001,(4):17-18

以ECMWF资料为因子，用PP法、MOS法、卡尔曼滤波法作平顶山地区日最高气温预报，并在微机上实现从格式转化、关键区选取、因子计算到结果输出的完全自动化。  相似文献   

OTF方法及其在GPS辅助航空摄影测量数据处理中的应用   总被引：9，自引：0，他引：9  

陈小明  刘基余 《测绘学报》1997,26(2):101-108

本文提出了一种基于伪距，载波相位双差卡尔曼滤波的ＯＴＦ方法，并成功地用它处理１９９６年５月在北京进行的ＧＰＳ辅助航空摄影测量动态定位数据。数据处理的结果表明，这种方法对于距离远达５０ｋｍ，高差大于２４００ｍ的ＤＧＰＳ测量能够迅速，有效地解算出正确的整周模糊度，在固定整周模糊度后可提供优于１ｄｍ的差分定位精度。此外，本文还提出了３种检验ＯＴＦ解算可靠性的方法。  相似文献   

GPS变形监测网的动态数据处理   总被引：7，自引：0，他引：7  

张华海  王爱生 《测绘学院学报》1999,(1)

叙述了用卡尔曼滤波方法处理GPS变形监测网的方法。推导了在地平坐标系中的观测方程和动态方程。实际计算结果表明,卡尔曼滤波可以用于GPS变形监测网的数据处理,其滤波估值精度优于静态平差。  相似文献