Dynamic ocean topography of the northern Nordic seas: a comparison between satellite altimetry and ocean modeling
Dynamic ocean topography of the northern Nordic seas: a comparison between satellite altimetry and ocean modeling
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DOI：
10.5194/tc-13-611-2019
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发表时间：
2019-02
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影响因子：
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通讯作者：
F. Müller;C. Wekerle;D. Dettmering;M. Passaro;W. Bosch;F. Seitz
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文献类型：
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作者：
F. Müller;C. Wekerle;D. Dettmering;M. Passaro;W. Bosch;F. Seitz
抽象的。极地海洋的动态海洋地形（DOT）可以通过卫星测高海面高度观测结合大地水准面信息以及海洋模型来描述。高度测量观测的特点是不规则采样和季节性海冰覆盖，使可靠的 DOT 估计变得复杂。模型显示各种时空分辨率，但仅限于其计算和数学背景以及引入的强迫模型。在本文中，ALES+ 重新跟踪的测高范围以及欧空局 Envisat 的沿轨 DOT 高度和有限元海冰海洋模型 (FESOM) 的水高度进行了比较，以研究相似性和差异。本文的目的是确定从测量和模型中得出的北欧北部海洋的模式和变化在多大程度上相互一致。研究期间涵盖2003年至2009年。关于季节性 DOT 变异性的评估分析显示出良好的一致性，并证实了两个数据集中年度信号的主导影响。基于估计的区域年度信号分量的比较显示，观测值的幅度强 2-3 倍，但相位一致。通过恒定偏移量和年度信号减少两个数据集，揭示了较小的区域残差和高度相关的 DOT 时间序列（皮尔逊线性相关系数至少为 0.67）。在无冰和受洋流影响的地区可以发现最高的相关性。然而，在海冰覆盖的陆架区域，差异是显而易见的。此外，观测数据中保持恒定的人工高程可归因于所使用的大地水准面的代表性不足。总体而言，北欧海域 DOT 的模拟描述和基于测高的描述之间的比较结果非常一致。
Abstract. The dynamic ocean topography (DOT) of the polar seas can be described by satellite altimetry sea surface height observations combined with geoid information as well as by ocean models. The altimetry observations are characterized by an irregular sampling and seasonal sea ice coverage complicating reliable DOT estimations. Models display various spatiotemporal resolutions but are limited to their computational and mathematical context and introduced forcing models. In the present paper, ALES+ retracked altimetry ranges and derived along-track DOT heights of ESA's Envisat and water heights of the Finite Element Sea Ice-Ocean Model (FESOM) are compared to investigate similarities and discrepancies. The goal of the present paper is to identify to what extent pattern and variability of the northern Nordic seas derived from measurements and model agree with each other, respectively. The study period covers the years 2003–2009. An assessment analysis regarding seasonal DOT variabilities shows good agreement and confirms the dominant impact of the annual signal in both datasets. A comparison based on estimated regional annual signal components shows 2–3 times stronger amplitudes of the observations but good agreement of the phase. Reducing both datasets by constant offsets and the annual signal reveals small regional residuals and highly correlated DOT time series (Pearson linear correlation coefficient of at least 0.67). The highest correlations can be found in areas that are ice-free and affected by ocean currents. However, differences are visible in sea-ice-covered shelf regions. Furthermore, remaining constant artificial elevations in the observational data can be attributed to an insufficient representation of the used geoid. In general, the comparison results in good agreement between simulated and altimetry-based descriptions of the DOT in the northern Nordic seas.