The global three-dimensional variational(3D-Var)data assimilation is implemented on a new quasi-uniform overset(Yin-Yang)grid on sphere.As a quasi-uniform spherical grid,it covers the sphere by overlapping two perpend...The global three-dimensional variational(3D-Var)data assimilation is implemented on a new quasi-uniform overset(Yin-Yang)grid on sphere.As a quasi-uniform spherical grid,it covers the sphere by overlapping two perpendicularly oriented grid components which is nothing but low latitude region of the usual latitude-longitude grid.Based on this characteristic of the Yin-Yang grid,it enables us to implement the regional 3D-Var system efficiently and accurately on the Yin or Yang component grid,respectively.The global analysis could update directly from the regional analysis since they have the same configurations like the precondition of eigenvalue decomposition for vertical direction,recursive filtering for horizontal direction,minimization method and observation operator and so on.However,the balance equation and vector wind are needed to be paid more attention on the Yin grid analysis due to its coordinate transformation.How to spread the observation information near the boundary of Yin and Yang grid is a key to the 3D-Var analysis.Extending double the horizontal correlation length distance in the overset boundary of Yin and Yang grid has successfully solved the problem.The results show that the analysis on the Yin-Yang grid is reasonable and similar to the result on the latitude-longitude(LAT-LON)grid.This paper provides a promising strategy for the development of a 3D-Var global system for overset grids.展开更多
This paper proposes a new method for data assimilation of the surface radial current observed by High Frequency ground wave radar and optimization of the bottom friction coefficient.In this method,the shallow water wa...This paper proposes a new method for data assimilation of the surface radial current observed by High Frequency ground wave radar and optimization of the bottom friction coefficient.In this method,the shallow water wave equation is introduced into the cost function of the multigrid three-dimensional variation data assimilation method as the weak constraint term,the surface current and the bottom friction coefficient are defined as the analytical variables,and the high spatiotemporal resolution surface radial flow observed by the high-frequency ground wave radar is used to optimize the surface current and bottom friction coefficient.This method can effectively consider the spatiotemporal correlation of radar data and extract multiscale information from surface radial flow data from long waves to short waves.Introducing the shallow water wave equation into the cost function as a weak constraint condition can adjust both the momentum and mass fields simultaneously to obtain more reasonable analysis information.The optimized bottom friction coefficient is introduced into the regional ocean numerical model to carry out numerical experiments.The test results show that the bottom friction coefficient obtained by this method can effectively improve the accuracy of the numerical simulation of sea surface height in the offshore area and reduce the simulation error.展开更多
目的探讨3D打印技术在小儿后天性肘内翻畸形截骨矫形术中的临床应用价值。方法收集2016年6月至2018年8月由重庆大学附属三峡医院小儿外科收治的16例肘内翻畸形患者作为研究对象,均行截骨矫形手术治疗。其中男童10例,女童6例,平均年龄7....目的探讨3D打印技术在小儿后天性肘内翻畸形截骨矫形术中的临床应用价值。方法收集2016年6月至2018年8月由重庆大学附属三峡医院小儿外科收治的16例肘内翻畸形患者作为研究对象,均行截骨矫形手术治疗。其中男童10例,女童6例,平均年龄7.7岁。术前根据HSS(Hospital for Special Surgery)肘关节评分标准评价肘关节功能,行肘关节CT扫描,建立数字模型,按照1∶1等比例打印3D实体模型,在模型上设计截骨平面,术中参照3D模型实施截骨矫形。手术后6个月复查,采用HSS肘关节评分标准评价肘关节功能,拍摄肘关节正侧位X线片测量肘关节提携角、肱骨前倾角和鲍曼角,并与术前设计进行比较,评价矫形效果是否符合预期。结果16例患者均在全麻下顺利完成手术,术后均获随访,所有患者获骨性愈合,肘内翻畸形获得矫正,无神经血管损伤、术区感染、克氏针移位等并发症发生。3D模型模拟手术效果:提携角范围为9°~19°,平均(13.57±2.62)°;手术后6个月X线片结果:提携角范围为9°~19°,平均(14.34±3.28)°,前倾角范围为24°~51°,平均为(40.08±7.44)°,鲍曼角范围为55°~76°,平均为(67.54±6.10)°。3D模拟手术与实际手术后提携角对比,差异无统计学意义(t=1.76,P=0.1)。术后6个月随访时肘关节功能评定:优10例,良0例,一般5例,差1例。肘关节功能评分:69~100分,平均(89.00±11.62)分;与术前肘关节功能评分比较,差异无统计学意义(t=1.03,P=0.32)。结论在小儿肘关节畸形截骨矫形术中运用3D打印技术,有助于评估畸形形态和精确设计截骨角度,截骨矫形效果符合预期。展开更多
基金National Key R&D Program of China(2017YFC1501901,2017YFA0603901)。
文摘The global three-dimensional variational(3D-Var)data assimilation is implemented on a new quasi-uniform overset(Yin-Yang)grid on sphere.As a quasi-uniform spherical grid,it covers the sphere by overlapping two perpendicularly oriented grid components which is nothing but low latitude region of the usual latitude-longitude grid.Based on this characteristic of the Yin-Yang grid,it enables us to implement the regional 3D-Var system efficiently and accurately on the Yin or Yang component grid,respectively.The global analysis could update directly from the regional analysis since they have the same configurations like the precondition of eigenvalue decomposition for vertical direction,recursive filtering for horizontal direction,minimization method and observation operator and so on.However,the balance equation and vector wind are needed to be paid more attention on the Yin grid analysis due to its coordinate transformation.How to spread the observation information near the boundary of Yin and Yang grid is a key to the 3D-Var analysis.Extending double the horizontal correlation length distance in the overset boundary of Yin and Yang grid has successfully solved the problem.The results show that the analysis on the Yin-Yang grid is reasonable and similar to the result on the latitude-longitude(LAT-LON)grid.This paper provides a promising strategy for the development of a 3D-Var global system for overset grids.
基金supported by the National Natural Science Foundation of China (Nos. 41506039, 41776004, 41775100 and 41606039)the National Key Research and Development Program of China (No. 2016YFC1401800)+1 种基金the Fundamental Research Funds for the Central Universities (No. 2016B12514)the National Programme on Global Change and Air-Sea Interaction of China (No. GASI-IPO VAI-04)
文摘This paper proposes a new method for data assimilation of the surface radial current observed by High Frequency ground wave radar and optimization of the bottom friction coefficient.In this method,the shallow water wave equation is introduced into the cost function of the multigrid three-dimensional variation data assimilation method as the weak constraint term,the surface current and the bottom friction coefficient are defined as the analytical variables,and the high spatiotemporal resolution surface radial flow observed by the high-frequency ground wave radar is used to optimize the surface current and bottom friction coefficient.This method can effectively consider the spatiotemporal correlation of radar data and extract multiscale information from surface radial flow data from long waves to short waves.Introducing the shallow water wave equation into the cost function as a weak constraint condition can adjust both the momentum and mass fields simultaneously to obtain more reasonable analysis information.The optimized bottom friction coefficient is introduced into the regional ocean numerical model to carry out numerical experiments.The test results show that the bottom friction coefficient obtained by this method can effectively improve the accuracy of the numerical simulation of sea surface height in the offshore area and reduce the simulation error.
文摘目的探讨3D打印技术在小儿后天性肘内翻畸形截骨矫形术中的临床应用价值。方法收集2016年6月至2018年8月由重庆大学附属三峡医院小儿外科收治的16例肘内翻畸形患者作为研究对象,均行截骨矫形手术治疗。其中男童10例,女童6例,平均年龄7.7岁。术前根据HSS(Hospital for Special Surgery)肘关节评分标准评价肘关节功能,行肘关节CT扫描,建立数字模型,按照1∶1等比例打印3D实体模型,在模型上设计截骨平面,术中参照3D模型实施截骨矫形。手术后6个月复查,采用HSS肘关节评分标准评价肘关节功能,拍摄肘关节正侧位X线片测量肘关节提携角、肱骨前倾角和鲍曼角,并与术前设计进行比较,评价矫形效果是否符合预期。结果16例患者均在全麻下顺利完成手术,术后均获随访,所有患者获骨性愈合,肘内翻畸形获得矫正,无神经血管损伤、术区感染、克氏针移位等并发症发生。3D模型模拟手术效果:提携角范围为9°~19°,平均(13.57±2.62)°;手术后6个月X线片结果:提携角范围为9°~19°,平均(14.34±3.28)°,前倾角范围为24°~51°,平均为(40.08±7.44)°,鲍曼角范围为55°~76°,平均为(67.54±6.10)°。3D模拟手术与实际手术后提携角对比,差异无统计学意义(t=1.76,P=0.1)。术后6个月随访时肘关节功能评定:优10例,良0例,一般5例,差1例。肘关节功能评分:69~100分,平均(89.00±11.62)分;与术前肘关节功能评分比较,差异无统计学意义(t=1.03,P=0.32)。结论在小儿肘关节畸形截骨矫形术中运用3D打印技术,有助于评估畸形形态和精确设计截骨角度,截骨矫形效果符合预期。
