Interdecadal Sea Surface Temperature Variability in the Equatorial Pacific Ocean. Part I: The Role of Off-Equatorial Wind Stresses and Oceanic Rossby Waves
Interdecadal Sea Surface Temperature Variability in the Equatorial Pacific Ocean. Part I: The Role of Off-Equatorial Wind Stresses and Oceanic Rossby Waves
复制标题
赤道太平洋年代际海面温度变化。
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
S. Power
中科院分区：
文献类型：
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作者：
S. McGregor;N. Holbrook;S. Power
利用澳大利亚气象局研究中心的CGCM和一个线性的第一斜压模式海洋浅水模式（SWM），研究了赤道太平洋海表温度（SST）年代际变率的海洋动力强迫机制。对百年尺度CGCM模拟的13年低通Butterfly滤波SST距平的分析表明，SST距平的空间分布和时间变率与年代际太平洋涛动一致。从SWM模拟强迫与风应力从CGCM模拟的结果进行了比较，以及与CGCM，因此，SWM然后被用来调查的“非耦合”赤道风应力强迫，离赤道风应力强迫（OffEqWF），Rossby波反射在西太平洋边界的作用，在十年的赤道温跃层深度异常。赤道太平洋风应力被证明可以解释赤道温跃层深度异常的大部分总体方差。然而，12.5°纬度以外的OffEqWF在Nino-4（Nino-3）区域产生了一个年代际特征，解释了约10%（1.5%）的滤波控制模拟方差。西太平洋边界的Rossby波反射被证明是OffEqWF对这些赤道异常的贡献的基础。这一结果的可预测性的温跃层深度的年代际变化的影响进行了研究，结果表明，OffEqWF产生的赤道响应在Nino-3地区长达3年后，风应力强迫关闭。此外，在统计上显着的相关性被发现在赤道外区和Nino-3区域的温跃层深度异常，与Nino-3区域滞后约2年。作者的结论是，有潜在的可预测性的OffEqWF赤道温跃层深度异常的提前时间长达3年时，考虑到赤道外区域Rossby波的振幅和位置。
The Australian Bureau of Meteorology Research Centre CGCM and a linear first baroclinic-mode ocean shallow-water model (SWM) are used to investigate ocean dynamic forcing mechanisms of the equatorial Pacific Ocean interdecadal sea surface temperature (SST) variability. An EOF analysis of the 13-yr low-pass Butterworth-filtered SST anomalies from a century-time-scale CGCM simulation reveals an SST anomaly spatial pattern and time variability consistent with the interdecadal Pacific oscillation. Results from an SWM simulation forced with wind stresses from the CGCM simulation are shown to compare well with the CGCM, and as such the SWM is then used to investigate the roles of “uncoupled” equatorial wind stress forcing, off-equatorial wind stress forcing (OffEqWF), and Rossby wave reflection at the western Pacific Ocean boundary, on the decadal equatorial thermocline depth anomalies. Equatorial Pacific wind stresses are shown to explain a large proportion of the overall variance in the equatorial thermocline depth anomalies. However, OffEqWF beyond 12.5° latitude produces an interdecadal signature in the Nino-4 (Nino-3) region that explains approximately 10% (1.5%) of the filtered control simulation variance. Rossby wave reflection at the western Pacific boundary is shown to underpin the OffEqWF contribution to these equatorial anomalies. The implications of this result for the predictability of the decadal variations of thermocline depth are investigated with results showing that OffEqWF generates an equatorial response in the Nino-3 region up to 3 yr after the wind stress forcing is switched off. Further, a statistically significant correlation is found between thermocline depth anomalies in the offequatorial zone and the Nino-3 region, with the Nino-3 region lagging by approximately 2 yr. The authors conclude that there is potential predictability of the OffEqWF equatorial thermocline depth anomalies with lead times of up to 3 yr when taking into account the amplitudes and locations of off-equatorial region Rossby waves.