Pacific Decadal Oscillation and recent oxygen decline in the eastern tropical Pacific Ocean
Pacific Decadal Oscillation and recent oxygen decline in the eastern tropical Pacific Ocean
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DOI：
10.5194/bg-15-7111-2018
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发表时间：
2018-11-29
期刊：
影响因子：
4.9
通讯作者：
Boening, Claus W.
中科院分区：
文献类型：
--
作者：
Duteil, Olaf;Oschlies, Andreas;Boening, Claus W.
利用一个耦合的海洋环流-海洋地球化学模式，研究了太平洋年代际振荡（PDO）的正、负位相对东太平洋贫氧区扩展的影响。我们表明，在一个“典型的”PDO积极的阶段，体积的suboxic地区扩大了7%，超过50年，由于大规模流通的贸易风的强度下降有关的放缓。氧含量的变化主要是由10度N和10度S之间的平流过程控制，而扩散过程是主导向极地10度：在一个“典型的”PDO-正相的迟滞赤道流系统提供较少的氧气到东部赤道部分的盆地，而氧气输送的扩散过程显着减少南10度S。位于北纬10度以北的亚氧区显示出对PDO相的敏感性较低，因为与局部上升流相关的过程在设置氧浓度方面与大尺度环流相比起着主导作用。我们的研究表明，自1975年以来普遍存在的PDO阳性条件可能解释了东太平洋目前脱氧的重要部分。
The impact of the positive and negative phases of the Pacific Decadal Oscillation (PDO) on the extension of the poorly oxygenated regions of the eastern Pacific Ocean was assessed using a coupled ocean circulation-biogeochemical model. We show that during a "typical" PDO-positive phase the volume of the suboxic regions expands by 7% over 50 years due to a slowdown of the large-scale circulation related to the decrease in the intensity of the trade winds. Changes in oxygen levels are mostly controlled by advective processes between 10 degrees N and 10 degrees S, whereas diffusive processes are dominant poleward of 10 degrees : in a "typical" PDO-positive phase the sluggish equatorial current system provides less oxygen to the eastern equatorial part of the basin while the oxygen transport by diffusive processes significantly decreases south of 10 degrees S. The suboxic region located north of 10 degrees N displays less sensitivity to the phase of the PDO as the local upwelling-related processes play a dominant role compared to the large-scale circulation in setting the oxygen concentration. Our study suggests that the prevailing PDO-positive conditions since 1975 may explain a significant part of the current deoxygenation occurring in the eastern Pacific Ocean.