海洋线现象具有时空动态特性,其属性、功能和关系在空间、时间和时空上都发生变化,用传统的G IS数据模型来组织具有时空过程的海洋线数据面临许多挑战。针对海洋线的时空动态特征,在分析海洋线特性的基础上,提出基于特征的海洋线数据模...海洋线现象具有时空动态特性,其属性、功能和关系在空间、时间和时空上都发生变化,用传统的G IS数据模型来组织具有时空过程的海洋线数据面临许多挑战。针对海洋线的时空动态特征,在分析海洋线特性的基础上,提出基于特征的海洋线数据模型(Feature-Based M arine L ineData Model,FBMLDM)。采用面向对象技术设计UML的框架图,给出海洋线数据模型中的关系表模型和文件层次存储模型具体实现形式,从而进行海洋线数据的组织与管理。实验表明,该模型能够很好应用于具有时空过程的海洋线,也为海洋数据模型的总体设计提供借鉴。展开更多
The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 201 I. This study presents a quality assessment of HY-2A scatterometer （HYSCAT） data based on comparison with ocean ...The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 201 I. This study presents a quality assessment of HY-2A scatterometer （HYSCAT） data based on comparison with ocean buoy data, the Advanced Scatterometer （ASCAT） data, and numerical model data from the National Centers for Environmental Prediction （NCEP）. The in-situ observations include those from buoy arrays operated by the National Data Buoy Center （NDBC） and Tropical Atmosphere Ocean （TAO） project. Only buoys located offshore and in deep water were analyzed. The temporal and spatial collocation windows between HYSCAT data and buoy observations were 30 min and 25 km, respectively. The comparisons showed that the wind speeds and directions observed by HYSCAT agree well with the buoy data. The root-mean-squared errors （RMSEs） of wind speed and direction for the HYSCAT standard wind products are 1.90 m/s and 22.80°, respectively. For the HYSCAT-ASCAT comparison, the temporal and spatial differences were limited to 1 h and 25 km, respectively. This comparison yielded RMSEs of 1.68 m/s for wind speed and 19.1° for wind direction. We also compared HYSCAT winds with reanalysis data from NCEP. The results show that the RMSEs of wind speed and direction are 2.6 m/s and 26°, respectively. The global distribution of wind speed residuals （HYSCAT-NCEP） is also presented here for evaluation of the HYSCAT-retrieved wind field globally. Considering the large temporal and spatial differences of the collocated data, it is concluded that the HYSCAT-retrieved wind speed and direction met the mission requirements, which were 2 rn/s and 20° for wind speeds in the range 2-24 m/s. These encouraging assessment results show that the wind data obtained from HYSCAT will be useful for the scientific community.展开更多
文摘海洋线现象具有时空动态特性,其属性、功能和关系在空间、时间和时空上都发生变化,用传统的G IS数据模型来组织具有时空过程的海洋线数据面临许多挑战。针对海洋线的时空动态特征,在分析海洋线特性的基础上,提出基于特征的海洋线数据模型(Feature-Based M arine L ineData Model,FBMLDM)。采用面向对象技术设计UML的框架图,给出海洋线数据模型中的关系表模型和文件层次存储模型具体实现形式,从而进行海洋线数据的组织与管理。实验表明,该模型能够很好应用于具有时空过程的海洋线,也为海洋数据模型的总体设计提供借鉴。
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2013AA09A505)the National Natural Science Foundation of China(No.40906091)the Open Project of School of Marine Sciences,Nanjing University of Information Science and Technology(No.KHYS1304)
文摘The first Chinese microwave ocean environment satellite HY-2A was launched successfully in August, 201 I. This study presents a quality assessment of HY-2A scatterometer （HYSCAT） data based on comparison with ocean buoy data, the Advanced Scatterometer （ASCAT） data, and numerical model data from the National Centers for Environmental Prediction （NCEP）. The in-situ observations include those from buoy arrays operated by the National Data Buoy Center （NDBC） and Tropical Atmosphere Ocean （TAO） project. Only buoys located offshore and in deep water were analyzed. The temporal and spatial collocation windows between HYSCAT data and buoy observations were 30 min and 25 km, respectively. The comparisons showed that the wind speeds and directions observed by HYSCAT agree well with the buoy data. The root-mean-squared errors （RMSEs） of wind speed and direction for the HYSCAT standard wind products are 1.90 m/s and 22.80°, respectively. For the HYSCAT-ASCAT comparison, the temporal and spatial differences were limited to 1 h and 25 km, respectively. This comparison yielded RMSEs of 1.68 m/s for wind speed and 19.1° for wind direction. We also compared HYSCAT winds with reanalysis data from NCEP. The results show that the RMSEs of wind speed and direction are 2.6 m/s and 26°, respectively. The global distribution of wind speed residuals （HYSCAT-NCEP） is also presented here for evaluation of the HYSCAT-retrieved wind field globally. Considering the large temporal and spatial differences of the collocated data, it is concluded that the HYSCAT-retrieved wind speed and direction met the mission requirements, which were 2 rn/s and 20° for wind speeds in the range 2-24 m/s. These encouraging assessment results show that the wind data obtained from HYSCAT will be useful for the scientific community.
