Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and-2
Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and-2
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DOI：
10.1029/2000jc900063
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发表时间：
2000-08-15
影响因子：
3.6
通讯作者：
Reverdin, G
中科院分区：
文献类型：
--
作者：
Ducet, N;Le Traon, PY;Reverdin, G
本文主要研究了1992年10月至1998年5月期间，利用TOPEX/Poseidon （T/P）和ERS-1和-2高度计测量数据对中尺度表层海洋环流的改进估计。经过仔细的相互校准和均匀化后，这些数据通过先进的全球客观分析方法合并，使我们能够纠正残留的长波误差，并使用现实的海洋动力学相关尺度。高分辨率（0.25度x 0.25度）合并的T/P + ERS-1和-2海平面异常图比单独的数据集提供更均匀和更小的制图误差，比单独的T/P数据更真实的海平面和地转速度统计。此外，合并的T/P + ERS-1和-2图产生的涡流动能（EKE）水平比单独的T/P图高30%。它们还允许对EKE的东部和北部组成部分及其季节变化进行现实的全球估计，以便更好地研究EKE来源。与世界海洋环流实验中北大西洋海面漂浮物的速度统计结果比较，结果吻合得很好。与不同海洋状态下的当代海流计数据的比较也产生了类似的能量水平和类似的北向和东向能量比率，表明这些图适合于研究各向异性。图中海流的T/P + ERS纬向和经向分量通常呈现相当的均势变率，尽管大西洋的变率比太平洋的更各向同性，太平洋表现出强烈的纬向变化。EKE地图提供了非常详细的描述，可能以前从未在全球范围内实现过。在太平洋东北部、大西洋东北部和西北部、热带海洋，以及印度洋和西太平洋以南纬20度附近为中心、北太平洋西北部以北纬20度为中心的纬向延伸带，都有明显的季节变化。
This study focuses on the improved estimation of mesoscale surface ocean circulation obtained by merging TOPEX/Poseidon (T/P) and ERS-1 and -2 altimeter measurements between October 1992 and May 1998. Once carefully intercalibrated and homogenized, these data are merged through an advanced global objective analysis method that allows us to correct for residual long wavelength errors and uses realistic correlation scales of ocean dynamics, The high-resolution (0.25 degrees x 0.25 degrees) merged T/P + ERS-1 and -2 sea level anomaly maps provide more homogeneous and reduced mapping errors than either individual data set and more realistic sea level and geostrophic velocity statistics than T/P data alone. Furthermore, the merged T/P + ERS-1 and -2 maps yield eddy kinetic energy (EKE) levels 30% higher than maps of T/P alone. They also permit realistic global estimates of east and north components of EKE and their seasonal variations, to study EKE sources better. A comparison of velocity statistics with World Ocean Circulation Experiment surface drifters in the North Atlantic shows very good agreement. Comparison with contemporary current meter data in various oceanic regimes also produces comparable levels of energy and similar ratios of northward and eastward energy, showing that the maps are suitable to studying anisotropy. The T/P + ERS zonal and meridional components of the mapped currents usually present comparable rms variability, even though the variability in the Atlantic is more isotropic than that in the Pacific, which exhibits strong zonal changes. The EKE map presents a very detailed description, presumably never before achieved at a global scale. Pronounced seasonal changes of the EKE are found in many regions, notably the northeastern Pacific, the northeastern and northwestern Atlantic, the tropical oceans, and the zonally extended bands centered near 20 degrees S in the Indian and western Pacific Oceans and at 20 degrees N in the northwestern nl Pacific.