Towards a dynamically balanced eddy-resolving ocean reanalysis: BRAN3
Towards a dynamically balanced eddy-resolving ocean reanalysis: BRAN3
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DOI：
10.1016/j.ocemod.2013.03.008
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发表时间：
2013-07-01
期刊：
影响因子：
3.2
通讯作者：
Schiller, Andreas
中科院分区：
文献类型：
--
作者：
Oke, Peter R.;Sakov, Pavel;Schiller, Andreas
海洋中涡旋的产生和演变在很大程度上是由于不可预测的不稳定，即使在很短的时间尺度上也是如此。因此，涡旋解析海洋再分析通常使用数据同化来定期调整模式状态。在这项研究中，我们介绍了第二代涡旋分辨海洋再分析的结果，它被证明比前一代更接近同化和保持观测；但在每次同化时对模式状态的调整要小得多。我们比较了澳大利亚地区的第二版和第三版的蓝链再分析(BRAN)。总体而言，BRAN3中的模型场与观测值之间的不匹配比BRAN2中的不匹配小5-28%。具体地说，对于BRAN3(BRAN_2)，海平面、上层海洋温度、上层海洋盐度和近地表速度分别在7.7厘米(9.7厘米)、0.68摄氏度(0.95摄氏度)、0.16PSU(0.18PSU)和20.2厘米/S(21.3厘米/S)范围内与观测值相匹配。我们还表明，应用于BRAN3的增量--在每个同化步骤应用的人工调整--通常比BRAN2中的等效调整小20%-50%。这导致我们得出结论，BRAN3的性能比BRAN2更具动态一致性，使其更适合于一系列应用，包括海洋变异性分析、极端事件和过程研究。(C)2013爱思唯尔有限公司。保留所有权利。
The generation and evolution of eddies in the ocean are largely due to instabilities that are unpredictable, even on short time-scales. As a result, eddy-resolving ocean reanalyses typically use data assimilation to regularly adjust the model state. In this study, we present results from a second-generation eddy-resolving ocean reanalysis that is shown to match both assimilated and with-held observations more closely than its predecessor; but involves much smaller adjustments to the model state at each assimilation. We compare version 2 and 3 of the Bluelink ReANalysis (BRAN) in the Australian region. Overall, the misfits between the model fields in BRAN3 and observations are 5-28% smaller than the misfits for BRAN2. Specifically, we show that for BRAN3 (BRAN2) the sea-level, upper ocean temperature, upper-ocean salinity, and near-surface velocity match observations to within 7.7 cm (9.7 cm), 0.68 degrees C (0.95 degrees C), 0.16 psu (0.18 psu), and 20.2 cm/s (21.3 cm/s) respectively. We also show that the increments applied to BRAN3 - the artificial adjustments applied at each assimilation step - are typically 20-50% smaller than the equivalent adjustments in BRAN2. This leads us to conclude that the performance of BRAN3 is more dynamically consistent than BRAN2, rendering it more suitable for a range of applications, including analysis of ocean variability, extreme events, and process studies. (C) 2013 Elsevier Ltd. All rights reserved.