Tropical Pacific Ocean thermocline depth reconstructions for the Last Glacial Maximum
Tropical Pacific Ocean thermocline depth reconstructions for the Last Glacial Maximum
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DOI：
10.1029/97pa00822
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发表时间：
1997-06
期刊：
影响因子：
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通讯作者：
D. Andreasen;A. Ravelo
中科院分区：
文献类型：
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作者：
D. Andreasen;A. Ravelo
我们评估了10个表层海洋（0 - 300 m）水文参数与热带太平洋（24 ° N-24 ° S）<3800 m岩心顶部浮游有孔虫丰度空间分布的关系。前三个区系因子负荷的空间分布（88%的方差）是最高度相关的地下变异（混合层深度，温跃层深度）和抗性物种百分比（RSP）。然而，RSP与溶解无关，但与温跃层深度有关。因子I（混合层物种G. Escherichiata，G. ruber）和因子III（G. ruber）之间可以通过G.第三因子中的红球藻。这两个组合空间上包括热带和赤道太平洋西部的深混合层区域，但与不同的水团属性。因子I和因子III负荷的组合显示出与温跃层深度的更高相关性（R ² = 0.70）。因子II负荷（主要由温跃层栖息物种N。dutertrei）与温跃层深度相关性最显着（R ² = 0.73）。大多数因子与海表温度（SST）的相关性不显著，表明SST不是热带太平洋浮游有孔虫物种分布的主要强迫因子。利用Imbrie-Kipp方法（残差标准差± 22 m（1 σ））计算了一个新的传递函数，用于由热带太平洋温跃层有孔虫丰度预测热带太平洋温跃层深度。额外的± 5-m误差归因于核心顶部数据库中的低物种计数。现代模拟技术（MAT）也被用来预测温跃层深度（残差标准差± 21米）。虽然IKM和MAT的末次冰期最大温跃层深度变化一般在误差范围内，但估计的变化在地理上是一致的，这表明海洋学对气候强迫的反应。我们估计，末次盛冰期的温跃层深度比现在浅，在8 ° S以南约20 m，可能是由于南太平洋反气旋向东北移动。IKM和MAT都估计沿沿着赤道的东西向温跃层斜率较陡，这表明在末次盛冰期，纬向风应力（步行者环流）得到加强。总的来说，对末次盛冰期的温跃层估计表明，两个半球的气候带都向赤道方向压缩。
We evaluate the relationship between ten surface ocean (0–300 m) hydrographic parameters and the spatial distribution of factor-analyzed core top planktonic foraminiferal abundances in the tropical Pacific Ocean (24°N–24°S) for core tops <3800 m. The spatial distribution of the first three faunal factor loadings (88% of the variance) are most highly correlated to subsurface variability (mixed layer depth, thermocline depth) and resistant species percent (RSP). However, RSP is not related to dissolution but is related to thermocline depth. Factor I (mixed layer species G. glutinata, G. ruber) and factor III (G. ruber) can be distinguished from each other by low abundances of G. glutinata in factor III. Both assemblages spatially comprise the deep mixed layer region of the western tropical and equatorial Pacific Ocean, but are associated with distinct water mass properties. A combination of Factor I and III loadings shows a higher correlation to thermocline depth (R² = 0.70). Factor II loadings (dominated by thermocline dwelling species N. dutertrei) are most significantly correlated with the thermocline depth (R² = 0.73). Most factors show only marginally significant correlation to sea surface temperatures (SSTs), indicating that SST is not the primary forcing factor on the planktonic foraminiferal species distributions in the tropical Pacific. A new transfer function was calculated to predict tropical Pacific thermocline depth from planktonic foraminifera abundances using the Imbrie-Kipp Method (IKM) (standard deviation of residuals ±22 m (1σ)). An additional ±5-m error is attributed to low species counts in the core top database. The modern analog technique (MAT) was also used to predict thermocline depth (standard deviation of residuals ±21 m). While last glacial maximum (LGM) thermocline depth changes by IKM and MAT were generally within error, estimated changes were geographically uniform, suggesting an oceanographic response to climate forcing. We estimate that the thermocline depth of the LGM was shallower than present by ∼20 m south of 8°S, possibly due to a shift in the South Pacific anticyclone to the northeast. Both the IKM and MAT estimate a steeper east-west thermocline slope along the equator, suggesting that zonal wind stress (Walker circulation) was intensified during the LGM. Collectively, the thermocline estimates for the LGM suggest an equatorward compression of the climate zones in both hemispheres.