Combined Ocean Tide Analysis by GRACE and Altimetry data (COTAGA)

GRACE 和高度测量数据的组合海洋潮汐分析 (COTAGA)

• 批准号: 30061353
• 负责人: Dr.-Ing. Wolfgang Bosch
• 金额: --
• 依托单位: Deutsches Geodätisches Forschungsinstitut
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/30061353?language=en
• 关键词: Combined; Ocean; Tide; Analysis; GRACE

Precise models of ocean tides are crucial because (i) the effect of ocean tides has to be removed from CHAMP and GRACE observations in order to obtain gravity field models describing exclusively the Earth gravity and (ii) altimetric sea surface heights should be ¿tidefree¿ in order to be comparable with each other and to be assimilated into numerical models. Deficiencies for ocean tides over continental shelves and in polar oceans are well known ¿ even for the most recent models. The present project therefore focuses on two strategies:1) Empirical improvements to the widely used state-of-the-art ocean tide model FES2004 by (a) solving residuals for major tidal constituents with a spatial resolution as short as 300 km from GRACE data only (long wavelength) and (b) applying response and harmonic analysis to multi-mission altimeter data to estimate in particular for shallow water areas corrections for the dominant tidal constituents and non-linear effect like M4 (short wavelength). Both, corrections will be validated and combined to an upgraded FES2004-model subsequently used for a more precise de-aliasing of the GRACE gravity field models and for improved corrections of altimetry data.2) Hydrodynamic modelling to further enhance the Hamburg Tide Model. Revising expertise these investigations shall provide a quantitative dynamical tide modelling with assimilation in open ocean and shallows sea, capable to overcome the deficiencies of current tide models.

精确的海洋潮汐模型是至关重要的，因为（i）海洋潮汐的影响必须从CHAMP和GRACE观测中去除，以获得专门描述地球重力的重力场模型，以及（ii）测高海面高度应该是无潮汐的，以便相互比较并被同化到数值模型中。大陆架上和极地海洋中的海洋潮汐的定义是众所周知的，即使是最新的模型。因此，本项目的重点是两个战略：1）对广泛使用的最先进的海潮模型FES 2004进行经验性改进，方法是：（a）仅从GRACE数据（长波长）中以短至300公里的空间分辨率求解主要潮汐成分的残差;（B）对多任务高度计数据进行响应和谐波分析，以估计特别是浅水区主要潮汐成分和M4（短波长）等非线性效应的校正。这两种校正都将得到验证，并与升级的FES 2004模型相结合，随后用于更精确地消除GRACE重力场模型的混叠，并改进测高数据的校正。这些调查将提供一个定量的动力潮汐模型，在公海和浅海进行同化，能够克服目前潮汐模型的不足。