基于HY-2卫星数据海流反演算法研究

发布时间：2018-05-02 10:22

本文选题：HY-2 + 网格化　；参考：《国家海洋环境预报中心》2015年硕士论文

【摘要】：海流是海水因热辐射、蒸发、降水、冷缩等而形成密度不同的水团,再加上风应力、地转偏向力、引潮力等作用而形成的大规模相对稳定的非周期性海水流动,它是海水的普遍运动形式之一,使世界大洋得以保持其各种水文和化学要素的长期相对稳定。获得海表流速的方式有随船海流计、浮标和通过卫星数据反演得到海流。卫星数据具有时间序列长,空间跨度大的特点,通过卫星数据反演得到海流不仅成本低,实际操作性高,而且覆盖范围广时间长,对于研究大尺度全球长时间序列的海流特征来说,数据更加丰富。海洋二号(HY-2)卫星是中国海洋动力环境探测系列卫星的首颗卫星,实现全天时、全天候对海面风场、海面高度场、浪场、海洋重力场、大洋环流和海表温度场等重要海洋参数的综合监测,其上装载了高度计、辐射计和散射计,能够提供反演海表流速的所需主要数据。因此,实现基于海洋二号卫星反演海流的技术流程具有重要的意义。该项工作主要包括：1. 对反演海表流速所需的原始数据进行预处理。对原始卫星高度计数据按照一定的筛选条件选出质量可靠的点,按照距离加权法进行网格化,得到1°×1°的海面动力高度场。由海洋二号卫星散射计数据产品经过插值得到1°×10海面风场和AMSR-2得到1°×1。海表温度场。2. 实现两种算法反演海流产品：经验模型算法和动力模型算法。经验模型算法的核心思想就是将海表流速分为两个部分：地转流和Ekman流。地转流是由经典的地转平衡方程得到,Ekman流由Ekman漂流理论实现。对于赤道处的海表流速计算采用f平面转换的方法。动力模型算法的核心是不仅考虑海面动力高度和风场,还加入了海表温度梯度场。对于赤道处的处理采用正交多项式拟合的数学方法。3. 将由经验模型算法和动力模型算法得到的基于海洋二号卫星数据的反演海流结果和OSCAR海流数据产品进行对比验证。结果表明两种算法结果在近赤道处较差,中高纬地区较好。两种算法标准差在近赤道处达到0.30m/s,在中高纬地区为0.05m/s到0.10m/s。第一种算法的标准差比第二种算法标准差较大。
[Abstract]:A current is a mass of water with different densities formed by heat radiation, evaporation, precipitation, condensation, and so on, coupled with wind stress, geostrophic deflection, tidal force, and so on, resulting in a large, relatively stable, aperiodic flow of seawater. It is one of the general movement forms of seawater, which enables the world ocean to maintain its hydrological and chemical elements relatively stable for a long time. The sea surface velocity can be obtained by current meter, buoy and inversion of satellite data. Satellite data has the characteristics of long time series and large space span. The inversion of satellite data not only has the advantages of low cost, high practical operation, but also wide coverage and long time. For studying the characteristics of large scale global long time series, the data are more abundant. The HY-2) satellite is the first satellite in a series of China's marine dynamic environmental exploration satellites. It has all-weather and all-weather responses to the wind field, sea height field, wave field, ocean gravity field, and so on. Integrated monitoring of important ocean parameters such as ocean circulation and sea surface temperature field, which is loaded with altimeters, radiometers and scattermeters, can provide the main data needed for inversion of sea surface velocity. Therefore, it is of great significance to realize the technical flow of ocean current inversion based on Ocean 2 satellite. The work consisted mainly of: 1. The raw data needed for inversion of sea surface velocity are preprocessed. According to the screening conditions of the original satellite altimeter data, the reliable points are selected, and the dynamic sea surface height field of 1 掳脳 1 掳is obtained by the distance weighting method. The sea surface wind field of 1 掳脳 10 and 1 掳脳 1 by AMSR-2 are obtained by interpolation from the data of Ocean 2 Satellite scatterometer. Sea surface temperature field. Two algorithms are implemented to retrieve current products: empirical model algorithm and dynamic model algorithm. The core idea of empirical model algorithm is to divide sea surface velocity into two parts: geostrophic current and Ekman current. The geostrophic flow is derived from the classical geostrophic equilibrium equation and the Ekman flow is realized by Ekman drift theory. For the calculation of sea surface velocity at the equator, the method of f plane conversion is used. The core of the dynamic model algorithm is not only considering the sea surface dynamic height and wind field, but also adding the sea surface temperature gradient field. The orthogonal polynomial fitting method is used to deal with the equator. The results obtained from empirical model algorithm and dynamic model algorithm based on ocean 2 satellite data are compared with OSCAR current data products. The results show that the results of the two algorithms are poor near the equator and are better in the middle and high latitudes. The standard deviations of the two algorithms are 0.30 m / s near the equator and 0.10 m / s / s at the middle and high latitudes. The standard deviation of the first algorithm is larger than that of the second.
【学位授予单位】：国家海洋环境预报中心
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P715.6;P731.21

【参考文献】