Tracer and observationally-derived constraints on diapycnal diffusivities in an ocean state estimate
Tracer and observationally-derived constraints on diapycnal diffusivities in an ocean state estimate
复制标题
海洋状态估计中示踪剂和观测得出的对二密扩散率的约束
DOI：
10.5194/os-2021-87
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发表时间：
2021
期刊：
影响因子：
3.2
通讯作者：
P. Heimbach
中科院分区：
文献类型：
--
作者：
D. Trossman;C. Whalen;T. Haine;A. Waterhouse;A. Nguyen;A. Bigdeli;M. Mazloff;P. Heimbach
摘要。使用海洋参数和状态估计框架-例如估计海洋环流和气候（ECCO）框架-可以提供一个机会来了解单观测无法由于覆盖范围的差距而导致的沉周期扩散系数参数（κρ）的空间分布。然而，我们表明，现有的原位温度、盐度和压力观测的同化不足以约束用ECCO估计的κρ，因为ECCO的κρ与观测结果不太一致，特别是从微观结构测量推断的κρ。我们研究了是否有更广泛的全球覆盖和更好理解的测量不确定度的观测值可以被ECCO吸收，以改善其对κρ的表示。argo衍生的κρ利用基于应变的细尺度水文结构参数化是一个潜在的信息来源。argo衍生的κρ与微观结构吻合良好。然而，由于Argo衍生的κρ具有测量和结构不确定性，我们建议溶解氧浓度作为未来ECCO数据同化的候选。我们使用ECCO进行敏感性分析，以测试氧浓度是否提供有关κρ的信息。我们比较了两种伴随灵敏度计算：一种对argo衍生的κρ使用不匹配，另一种对溶解氧浓度使用不匹配。我们发现溶解氧浓度的伴随灵敏度与状态估计的控制空间不匹配，通常会导致κρ相对于argo推导值和微观结构推断值有所改善。然而，溶解氧浓度的同化可能不能代替精确测量的κρ的同化。
Abstract. Use of an ocean parameter and state estimation framework–such as the Estimating the Circulation & Climate of the Ocean (ECCO) framework–could provide an opportunity to learn about the spatial distribution of the diapycnal diffusivity parameter (κρ) that observations alone cannot due to gaps in coverage. However, we show that the assimilation of existing in situ temperature, salinity, and pressure observations is not sufficient to constrain κρ estimated with ECCO, as κρ from ECCO does not agree closely with observations–specifically, κρ inferred from microstructure measurements. We investigate whether there are observations with more global coverage and well-understood measurement uncertainties that can be assimilated by ECCO to improve its representation of κρ. Argo-derived κρ using a strain-based parameterization of finescale hydrographic structure is one potential source of information. Argo-derived κρ agrees well with microstructure. However, because Argo- derived κρ has both measurement and structural uncertainties, we propose dissolved oxygen concentrations as a candidate for future data assimilation with ECCO. We perform sensitivity analyses with ECCO to test whether oxygen concentrations provide information about κρ. We compare two adjoint sensitivity calculations: one that uses misfits to Argo-derived κρ and the other uses misfits to dissolved oxygen concentrations. We show that adjoint sensitivities of dissolved oxygen concentration misfits to the state estimate's control space typically direct κρ to improve relative to the Argo-derived and microstructure-inferred values. However, assimilation of dissolved oxygen concentrations would likely not serve as a substitute for assimilating accurately measured κρ.
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影响因子：
6.8
作者：
S. Bachman;B. Fox‐Kemper;F. Bryan
通讯作者：
S. Bachman;B. Fox‐Kemper;F. Bryan
影响因子：
5.2
作者：
Duteil, O.;Oschlies, A.
通讯作者：
Oschlies, A.
影响因子：
3.5
作者：
Naveira Garabato A
通讯作者：
Naveira Garabato A
影响因子：
6.8
作者：
Loose, Nora;Heimbach, Patrick
通讯作者：
Heimbach, Patrick
影响因子：
42.1
作者：
C. Whalen;C. de Lavergne;A. N. Naveira Garabato;J. Klymak;J. MacKinnon;K. Sheen
通讯作者：
C. Whalen;C. de Lavergne;A. N. Naveira Garabato;J. Klymak;J. MacKinnon;K. Sheen