Internal lee wave closures: Parameter sensitivity and comparison to observations
Internal lee wave closures: Parameter sensitivity and comparison to observations
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DOI：
10.1002/2015jc010892
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发表时间：
2015-12
影响因子：
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通讯作者：
D. Trossman;S. Waterman;K. Polzin;B. Arbic;S. Garner;A. Naveira-Garabato;K. Sheen
中科院分区：
文献类型：
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作者：
D. Trossman;S. Waterman;K. Polzin;B. Arbic;S. Garner;A. Naveira-Garabato;K. Sheen
本文研究了两种与海洋模式一起使用的内部背风波闭合，以预测与背风波和地形阻塞相关的时间平均全球能量转换率和耗散率：Garner（2005）方案和Bell（1975）理论。在两个南大洋地区的地转流占主导地位的潮汐关闭预测进行检查和比较的湍流动能耗散率，后者被假定为反映与地形阻塞和产生的背风波能量耗散的微观结构廓线观测。结果表明，当应用到这些南大洋地区，两个封闭最不同的地形阻塞的治疗。由于几个原因，逐点验证的封闭是不可能使用现有的观测，但封闭的预测和观测之间的水平平均比较。当考虑到底层地形的各向异性时，海底附近的两个水平平均闭合预测值大致相等。Garner（2005）方案预测了与地形阻塞相关的耗散，以解释水柱底部1000 m的大部分深度积分耗散，其中水平平均预测值完全在水平平均观测值的空间变异性范围内。Garner（2005年）方案所作的不适合海洋环境的简化，加上观测信息不完善，可以部分解释预测-观测不一致的原因，特别是在上层水柱。
This paper examines two internal lee wave closures that have been used together with ocean models to predict the time-averaged global energy conversion rate into lee waves and dissipation rate associated with lee waves and topographic blocking: the Garner (2005) scheme and the Bell (1975) theory. The closure predictions in two Southern Ocean regions where geostrophic flows dominate over tides are examined and compared to microstructure profiler observations of the turbulent kinetic energy dissipation rate, where the latter are assumed to reflect the dissipation associated with topographic blocking and generated lee wave energy. It is shown that when applied to these Southern Ocean regions, the two closures differ most in their treatment of topographic blocking. For several reasons, pointwise validation of the closures is not possible using existing observations, but horizontally averaged comparisons between closure predictions and observations are made. When anisotropy of the underlying topography is accounted for, the two horizontally averaged closure predictions near the seafloor are approximately equal. The dissipation associated with topographic blocking is predicted by the Garner (2005) scheme to account for the majority of the depth-integrated dissipation over the bottom 1000 m of the water column, where the horizontally averaged predictions lie well within the spatial variability of the horizontally averaged observations. Simplifications made by the Garner (2005) scheme that are inappropriate for the oceanic context, together with imperfect observational information, can partially account for the prediction-observation disagreement, particularly in the upper water column.