IRD, Noumea, BP A5, New Caledonia.
Mar Pollut Bull. 2010;61(7-12):432-48. doi: 10.1016/j.marpolbul.2010.06.043. Epub 2010 Aug 11.
An outstanding characteristic of New Caledonia upwelling is that most events appear limited to the southern half of the western barrier reef. This north-south difference cannot be explained by alongshore variability of the projected wind stress and no strong evidence for alternative explanations has been proposed. A major objective of this paper is to provide the first dynamical analysis of New Caledonia upwelling and its regional environment, based on numerical simulations. Coastal upwelling around New Caledonia is shown to be modulated by a system of geostrophic currents interacting with the island mass. Upwelling velocities are weaker than expected from the two-dimensional Ekman theory, as Ekman divergence is balanced by "coastal geostrophic convergence". The cooling effect of upwelling is also attenuated by alongshore transport of warm water by the Alis current, reminiscent of the Leeuwin current off Western Australia. Nevertheless, coastal upwelling can locally modify the large-scale surface water heat budget, dominated by meridional advection warming and surface cooling. The upwelled waters appear to be mostly of western origin and are transported below the surface by the Subtropical Counter Current before upwelling off New Caledonia. This appears in sharp contrast with the eastern barrier reef where the general warming by meridional advection of tropical surface waters is accentuated by the vigorous western boundary type Vauban current.
新喀里多尼亚上升流的一个显著特点是，大多数事件似乎仅限于西部屏障礁的南部。这种南北差异不能用预测风应力的沿岸变化来解释，也没有提出强有力的替代解释的证据。本文的主要目的是基于数值模拟，对新喀里多尼亚上升流及其区域环境进行首次动力分析。结果表明，新喀里多尼亚周围的上升流是由与岛屿质量相互作用的地转流系统调制的。上升流速度比二维埃克曼理论所预期的要弱，因为埃克曼辐散被“沿海地转辐合”所平衡。上升流的冷却效应也被阿利兹洋流的沿海水体输送所减弱，这让人想起西澳大利亚的利文洋流。尽管如此，上升流仍可局部改变由经向平流增暖主导的大尺度表层水热量收支，局部加热近岸水。上升流的水主要来自西部，在新喀里多尼亚附近上升之前，被亚热带逆流带到海面以下。这与东部屏障礁形成鲜明对比，在东部屏障礁，由于热带表面水的经向平流的强烈增暖，加剧了 Vauban 型西部边界流的影响。
