基于传输函数标准形态模式的海洋涡旋温盐和压力异常三维结构交互可视化

随着海洋观测技术和海洋数值模拟技术的发展，海洋学家已经能够获取海量的时空连续的海洋数据。但目前人们对于三维海洋大数据缺乏高效的交互可视探索手段，因此，利用科学可视化技术展现海洋数据，以及更深一步地挖掘时空数据规律是建立对海洋大数据从感知到认知的关键技术桥梁。本文利用体绘制技术从传输函数特征点数量、特征颜色映射以及表现特征的线型三个方面，设计针对海洋温盐异常数据以及压力异常数据的传输函数标准形态模式，能够直观有效地表现海洋涡旋温盐和压力异常三维结构。本文优化了球面光线投射算法，在保证绘制质量的情况下，实现了大规模海洋三维涡旋实时交互展示；同时实现了三维数据的内部漫游功能，能够更加清晰且完整地表现局部海洋涡旋的三维结构。通过可视分析发现，处于黑潮延伸体附近的气旋涡(CE, Cyclone Eddy)温度异常呈“上正下负”的三维结构；由于涡旋引起的海水升降运动，部分反气旋涡(AE, Anticyclone Eddy)盐度异常呈现出“上正下负”的三维结构；相较于温盐异常结构，海洋涡旋压力异常结构轮廓更为清晰且不会出现上下不一致的情况。

Visualization of three-dimensional thermohaline and pressure anomaly structure of ocean eddies based on standard morphological models of transfer functions

With the development of ocean observation technology and ocean numerical simulation technology, oceanographers have been able to obtain massive ocean data. However, the effective utilization of ocean big data is still very low at present. The use of scientific visualization technology to display marine data and further use of visual analysis technology to mine the laws of spatio-temporal data is a key technical bridges from perception to cognition. In this paper, we use volume rendering technology from the number of feature points, feature color mapping and the line shape to design a standard morphological model of the transfer function for ocean thermohaline anomaly data and pressure anomaly data. It can visually represent the three-dimensional structure of ocean eddy thermohaline anomaly and pressure anomaly. In this paper, we optimize the spherical ray casting algorithm to realize the large-scale ocean 3D eddies display under the condition of ensuring the rendering quality. At the same time, we have realized the internal roaming function of volume data, which can more clearly and completely represent the three-dimensional structure of ocean eddies. In this paper, it is found through visual analysis that the CE temperature anomaly near the Kuroshio extension has a three-dimensional structure of upper positive anomaly and lower negative anomaly. Due to the up-and-down motion of seawater caused by eddies, some AE salinity anomaly show a three-dimensional structure of upper positive anomaly and lower negative anomaly. Compared with the thermohaline anomaly structure, the outline of the ocean eddy pressure anomaly structure is clearer and there will be no inconsistency between?the upper and lower layers.