论文标题
上海pycnocline的季节性气候
A seasonal climatology of the upper ocean pycnocline
论文作者
论文摘要
基于温度/密度阈值或混合方法，已使用多个定义提供了混合层深度（MLD）的气候。位于混合层基础下方的上海洋pycnocline（UOP）的表征仍然很差，尽管该过渡层是海面层的无处不在的特征。可用的水文剖面提供了世界海洋的几乎全球覆盖范围，并用于建立UOP特性的季节性气候 - 强度，深度，厚度 - 以表征上海分层的空间和季节性变化。最大的分层值$ \ MATHCAL {O}（10^{ - 3} \，s^{ - 2}）$是在自动带中找到的，其中UOP的季节性变化也很小。最深的（$> $ 200 m）和最小分层的$ \ Mathcal {o}（10^{ - 6} \，s^{ - 2}）$ UOPS在冬季沿南极圆极电流（ACC）和北大西洋的高纬度地区在冬季发现。 UOP厚度的中位数为23 m，季节性和空间变化有限。只有少数区域的UOP厚度超过35 m。 UOP性质允许表征上海洋限制，通常发生在早春，通常与较大的可变性有关。根据该地区的不同，这种限制可能逐渐发生，就像在岩石高原周围一样，或者像在黑鲁希奥延伸中一样突然发生。冬季，UOP也可能与永久性的pycnocline间歇性合并。 UOP的上限最终与MLD估计值一致，除了在少数值得注意的地区，例如在太平洋温暖池中很重要，在冬季，在北太平洋高纬度地区。
Climatologies of the mixed layer depth (MLD) have been provided using several definitions based on temperature/density thresholds or hybrid approaches. The upper ocean pycnocline (UOP) that sits below the mixed layer base remains poorly characterised, though this transition layer is an ubiquitous feature of the ocean surface layer. Available hydrographic profiles provide near-global coverage of the world's ocean and are used to build a seasonal climatology of UOP properties -- intensity, depth, thickness -- to characterise the spatial and seasonal variations of upper ocean stratification. The largest stratification values $\mathcal{O}(10^{-3}\,s^{-2})$ are found in the intertropical band, where seasonal variations of the UOP are also very small. The deepest ($>$ 200 m) and least stratified $\mathcal{O}(10^{-6}\,s^{-2})$ UOPs are found in winter along the Antarctic Circumpolar Current (ACC) and at high latitudes of the North Atlantic. The UOP thickness has a median value of 23 m with limited seasonal and spatial variations; only a few regions have UOP thicknesses exceeding 35 m. The UOP properties allow the characterisation of the upper ocean restratification that generally occurs in early spring and is generally associated with large variability. Depending on the region, this restratification may happen gradually as around the Rockall plateau or abruptly as in the Kuroshio Extension. The UOP is also likely to merge intermittently with the permanent pycnocline in winter. The upper limit of the UOP is eventually consistent with MLD estimates, except in a few notable regions such as in the Pacific Warm Pool where barrier layers are important, and during wintertime at high latitudes of the North Pacific.
