Decadal Sea Level Variability in the South Pacific in a Global Eddy-Resolving Ocean Model Hindcast
Decadal Sea Level Variability in the South Pacific in a Global Eddy-Resolving Ocean Model Hindcast
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DOI：
10.1175/2007jpo3915.1
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发表时间：
2008-08
影响因子：
3.5
通讯作者：
Y. Sasaki;S. Minobe;N. Schneider;T. Kagimoto;M. Nonaka;H. Sasaki
中科院分区：
文献类型：
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作者：
Y. Sasaki;S. Minobe;N. Schneider;T. Kagimoto;M. Nonaka;H. Sasaki
使用地球模拟器 (OFES) 涡旋解析海洋环流模型 (OGCM) 的后报模拟，以及 1970 年以来潮汐计的海平面数据和 1992 年以来卫星高度计的海平面数据，研究了 1970 年至 2003 年南太平洋的海平面变化和相关海洋变化。OFES 的海平面异常 (SLA) 的第一个经验正交函数模式在南太平洋中部和西部。相应的主成分表示大致稳定的高、低和高 SLA，其间隔是 1970 年代末海平面快速下降和 1990 年代末海平面上升，这与潮汐计和卫星观测结果一致。这些年代际变化伴随着1000米深度的副热带环流环流变化，以及塔斯曼锋周围上层海洋纬向流和涡流活动的变化。与之前的相关研究基本一致，如果考虑到新西兰的影响，塔斯曼海海平面的变化可以通过风应力旋度异常迫使长斜压罗斯贝波的传播来解释。相应的大气变化与厄尔尼诺南方涛动（ENSO）的年代际变化有关。因此，过去三十年半南太平洋西部和中部海平面的年代际变化与ENSO的年代际变化可能存在关联。 20世纪90年代海平面上升与全球变暖引起广泛关注，这很可能与热带太平洋十年间变冷有关。
Sea level variability and related oceanic changes in the South Pacific from 1970 to 2003 are investigated using a hindcast simulation of an eddy-resolving ocean general circulation model (OGCM) for the Earth Simulator (OFES), along with sea level data from tide gauges since 1970 and a satellite altimeter since 1992. The first empirical orthogonal function mode of sea level anomalies (SLAs) of OFES exhibits broad positive SLAs over the central and western South Pacific. The corresponding principal component indicates roughly stable high, low, and high SLAs, separated by a rapid sea level fall in the late 1970s and sea level rise in the late 1990s, consistent with tide gauge and satellite observations. These decadal changes are accompanied by circulation changes of the subtropical gyre at 1000-m depth, and changes of upper-ocean zonal current and eddy activity around the Tasman Front. In general agreement with previous related studies, it is found that sea level variations in the Tasman Sea can be explained by propagation of long baroclinic Rossby waves forced by wind stress curl anomalies, if the impact of New Zealand is taken into account. The corresponding atmospheric variations are associated with decadal variability of El Nino– Southern Oscillation (ENSO). Thus, decadal sea level variability in the western and central South Pacific in the past three and half decades and decadal ENSO variability are likely to be connected. The sea level rise in the 1990s, which attracted much attention in relation to the global warming, is likely associated with the decadal cooling in the tropical Pacific.