伴随模式同化系统在修正模式误差中的应用研究   总被引：1，自引：1，他引：1  

杜钦  沈桐立 《热带气象学报》2007,23(2):182-188

资料误差和模式误差都是制约数值预报结果准确性提高的关键因素,传统四维资料同化都是假设模式完全正确仅对初始资料进行修正,忽略了模式误差本身造成的预报误差。伴随模式同化系统不仅具有修正资料误差的能力,也可应用于修正模式误差方面的研究。本文将卫星中心导风系统提供的GMS5卫星风场与非常规温度资料用于MM5伴随同化系统修正模式地形误差进行试验性研究表明,该方法能够反演出一个既与初始气象要素场相匹配,又与模式更协调的地形场,得到比一般包络地形更好的效果,改善模式对强降水中心及降水区域的预报;数值试验结果还揭示模式误差对模式预报造成一定的影响,用伴随方法对观测资料进行修正的同时也对模式误差进行修正的方法是可行的。  相似文献   

拟准检定法在TWSTFT数据预处理中的应用     

王常何  李伟超  欧吉坤  杨旭海 《时间频率学报》2013,(4)

基于双向卫星时间频率传递（TWSTFT）基本原理,建立了关于观测值真误差的数学模型,该模型是秩亏的。为了有效地克服模型的秩亏问题,首先设计了参数合并算法;然后将拟准检定法（QUAD）应用到数据预处理中。设计了适当的计算流程,解决了粗差检测问题。分别用仿真和实测数据进行了验证。  相似文献   

数字化曲线的附加系统参数平差     

孙同贺  闫国庆 《北京测绘》2013,(3):10-12

针对一般地图数字化曲线拟合方法的不足,提出了利用附加系统参数平差计算拟合曲线的参数。在参数平差中,将数字化曲线的X坐标和Y坐标均看作观测值,综合处理偶然误差和系统误差的联合影响,并评定精度。用t分布对系统参数进行显著性检验,结果表明附加系统参数模型正确。  相似文献   

Rule‐based Integration of Remotely‐sensed Data and GIS for Land Cover Mapping in NE Costa Rica     

Kenneth L. Driese  William A. Reiners  Robert C. Thurston 《国际地球制图》2013,28(1):37-46

Abstract

A classification method was developed for mapping land cover in NE Costa Rica at a regional scale for spatial input to a biogeochemical model (CENTURY). To distinguish heterogeneous cover types, unsupervised classifications of Landsat Thematic Mapper data were combined with ancillary and derived data in an iterative process. Spectral classes corresponding to ground control types were segregated into a storage raster while ambiguous pixels were passed through a set of rules to the next stage of processing. Feature sets were used at each step to help sort spectral classes into land cover classes. The process enabled different feature sets to be used for different types while recognizing that spectral classification alone was not sufficient for separating cover types that were defined by heterogeneity. Spectral data included the TM reflective bands, principal components and the NDVI. Ancillary data included GIS coverages of swamp extents, banana plantation boundaries and river courses. Derived data included neighborhood variety and majority measures that captured texture. The final map depicts 18 land cover types and captures the general patterns found in the region. Some confusion still exists between closely related types such as pasture with different amounts of tree cover.  相似文献   

Solute and gas geothermometry of geothermal wells: a geochemometrics study for evaluating the effectiveness of geothermometers to predict deep reservoir temperatures     

《International Geology Review》2012,54(16):2015-2049

Deep reservoir temperatures of 10 important geothermal systems of the world were estimated by applying 13 solute (Na/K) and 21 gas geothermometers. The predicted temperatures were comprehensively evaluated and compared with measured bottom-hole temperatures using geochemometric techniques. The present study reveals (1) high prediction performances in most of the Na/K geothermometers for the majority of the geothermal fields with liquid-dominated reservoirs, whereas low prediction performances were indicated for the geothermal fields with vapour-dominated and high-temperature reservoirs; (2) the gas geothermometers, in comparison to Na/K, are more successful in predicting the subsurface temperatures in high-temperature geothermal systems; (3) the geothermal systems for which Na/K geothermometers have indicated a high prediction performance, the gas geothermometers have specified a low prediction performances, and vice versa; (4) both Na/K and gas geothermometers, generally, overestimated the reservoir temperatures for the majority of the low-enthalpy geothermal fields and underestimated for the majority of the high-enthalpy geothermal fields; (5) the reservoir temperature predictions of gas geothermometers have more scatter than those temperatures inferred from Na/K geothermometers; and (6) in general, Na/K geothermometers seem to be a more successful geochemical tool in predicting reliable reservoir temperatures than gas geothermometers.  相似文献   

Robust algorithms for polyhedral modelling of fractured rock mass structure     

《Computers and Geotechnics》2013

This paper presents robust algorithms for application in polyhedral modelling of rock mass structure based on discrete fracture networks. The algorithms improve the robustness of current polyhedral modellers to challenging or degenerate geometries and geometrical errors. These issues are inevitably encountered when the fracture network realisations incorporate large numbers of fractures, or regions of densely packed fractures are modelled, or when the number of fracture network realisations interrogated is large. Several stages in the polyhedral modelling process which are sensitive to geometrical errors are reviewed and algorithms which are robust and capable of handling topological errors in the input fracture network geometry are presented.  相似文献   

融合多源数据的局部重力场建模中线性化误差的研究     

吴怿昊  罗志才 《大地测量与地球动力学》2016,36(6):476

引入高阶重力场模型作为参考场,削弱局部重力场逼近中线性化误差的影响。以实测的陆地重力异常、船载重力异常及航空重力扰动为基础数据,基于泊松小波径向基函数分析不同参考场对局部重力场逼近的影响。结果表明,引入高阶全球重力场模型代替GRS80参考椭球正常场作为参考场,能更为准确地逼近真实的重力场,有效削弱线性化误差的影响。相比于基于GRS80正常场构建的似大地水准面模型,基于DGM1S重力场模型为参考场构建的似大地水准面的精度,在地形起伏较大的德国、英国及挪威区域分别提高了1.5 mm、3.3 mm和9.0 mm。  相似文献   

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沈强  乔学军  金银龙  汪汉胜  江利明 《大地测量与地球动力学》2012,32(2):1-6

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王延停  归庆明  张倩倩 《大地测量与地球动力学》2012,32(2):51-54

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刘陶胜  黄声享  李沛鸿 《大地测量与地球动力学》2012,32(1):80-83

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