Time Variations in Ocean Bottom Pressure from a Few Hours to Many Years: In Situ Data, Numerical Models, and GRACE Satellite Gravimetry
Time Variations in Ocean Bottom Pressure from a Few Hours to Many Years: In Situ Data, Numerical Models, and GRACE Satellite Gravimetry
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DOI：
10.1029/2018jc014108
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发表时间：
2018-08
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影响因子：
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通讯作者：
L. Poropat;H. Dobslaw;L. Zhang;A. Macrander;O. Boebel;M. Thomas
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作者：
L. Poropat;H. Dobslaw;L. Zhang;A. Macrander;O. Boebel;M. Thomas
从全球154个不规则分布的不同位置获得的原位海底压力(OBP)被仔细处理，以分离与海洋环流和大尺度海平面变化有关的信号。与全球数值海洋模式实验的比较表明，在24小时以下的时间段内，一致性较差，可能与剩余的潮汐信号和应用于海洋模型的大气强迫中的小时间误差有关。在3至10天期间，对应关系迅速增加，因为风驱动的动力学已经被很好地理解，并因此被很好地应用到数值模式中。在30天左右或更长的时间内，一致性再次下降，在这些时间段，随着重压海平面变化变得更加重要，海洋大气环流模式中没有实施的过程。从德国地球科学研究中心RL05a重力场获得的现场数据与卫星OBP之间的对应关系关键取决于二级斯托克斯系数的后处理，其中还包括为基于GRACE的质量异常选择适当的平均区。对其他可用的GRACE Level-2产品的评估表明，更新的解决方案更适合ITSG-Grace2016和空间研究和喷气推进实验室RL05 Mascons。然而，考虑到OBP的强高频分量，海洋GRACE产品的较高时间分辨率将是相当有利的。
In situ ocean bottom pressure (OBP) obtained from 154 different locations irregularly scattered over the globe is carefully processed to isolate signals related to the ocean general circulation and large‐scale sea level changes. Comparison against a global numerical ocean model experiment indicates poor correspondence for periods below 24 hr, possibly related to residual tidal signals and small timing errors in the atmospheric forcing applied to the ocean model. Correspondence increases rapidly for periods between 3 and 10 days, where wind‐driven dynamics are already well understood and consequently well implemented into numerical models. Coherence decreases again for periods around 30 days and longer, where processes not implemented into ocean general circulation models as barystatic sea level changes become more important. Correspondence between in situ data and satellite‐based OBP as obtained from the Gravity Recovery and Climate Experiment (GRACE) German Research Centre for Geosciences RL05a gravity fields critically depends on the postprocessing of Level‐2 Stokes coefficients that also includes the selection of appropriate averaging regions for the GRACE‐based mass anomalies. The assessment of other available GRACE Level‐2 products indicates even better fit of more recent solutions as ITSG‐Grace2016 and the Center for Space Research and Jet Propulsion Laboratory RL05 mascons. In view of the strong high‐frequency component of OBP, however, a higher temporal resolution of the oceanic GRACE products would be rather advantageous.