Sea Surface Temperature Changes in the Northeastern Pacific Ocean during the Past 20,000 Years and Their Relationship to Climate Change in Northwestern North America
Sea Surface Temperature Changes in the Northeastern Pacific Ocean during the Past 20,000 Years and Their Relationship to Climate Change in Northwestern North America
复制标题
过去2万年东北太平洋海表温度变化及其与北美西北部气候变化的关系
作者：
Anne Sabin;N. Pisias
东北太平洋现代海气相互作用对北美西海岸的气候有显着影响。我们提出了过去 20,000 年的北太平洋东部基于放射虫微化石的温度重建，以研究千年时间尺度上大陆气候变化与东北太平洋海面温度 (SST) 变化之间可能的相关性和联系。重建表明，北美西海岸附近海洋环流的区域模式在距今 15,000 年的更南端。比今天更远，并在距今 13,000 卡路里前到达现在的位置。由于在距今 13,000 年之前北太平洋高压单元位于更南端，北太平洋漂移和过渡带进一步向南移动。虽然来自北美西北部的两个大陆古气候记录显示出区域差异，但它们也可以与海温变化相关。正如近海海表温度记录中所观察到的，北纬 48° 的沿海地区夏季温度显示出类似的模式。然而，内陆大陆记录似乎反映了更多区域尺度的海面条件变化，显示出热最大值集中在 10,000 cal yr B.P，这是在 42°N 以南的海洋横断面观察到的。我们的结论是，根据放射虫组合所反映的海洋变化模式，北太平洋漂移过去纬度位置的变化在控制其东部的大陆气候方面发挥了重要作用，就像在目前的环境中一样。我们还得出结论，在过去的 20,000 年中，海洋变化的演变很大程度上与东北太平洋的大气压力单元（北太平洋高压和阿留申低压）的迁移有关。
Modern ocean–atmosphere interactions in the northeastern Pacific Ocean have a significant effect on the climate of the west coast of North America. We present radiolarian microfossil-based temperature reconstructions for the eastern North Pacific spanning the past 20,000 yr to examine possible correlations and linkages between continental climate change and changes in sea surface temperature (SST) in the northeastern Pacific Ocean on millennial time scales. The reconstructions indicate that the regional pattern of ocean circulation off the west coast of North America was further south 15,000 cal yr B.P. than it is today, and reached its present location 13,000 cal yr B.P. The North Pacific Drift and Transition Zone were further south as a result of a more southerly North Pacific high pressure cell prior to 13,000 cal yr B.P. While two continental paleoclimate records from northwestern North America show regional differences, they also can be correlated to the SST changes. A coastal site at 48°N shows similar patterns in summer temperatures, as observed in offshore marine records of SSTs. However, an inland continental record seems to reflect more-regional-scale changes in sea surface conditions showing a thermal maximum centered at 10,000 cal yr B.P which is observed in the marine transect south of 42°N. We conclude, based on the pattern of oceanographic change as reflected in radiolarian assemblages, that changes in the past latitudinal position of the North Pacific Drift played a significant role in controlling continental climate immediately to its east, as it does in the present environment. We also conclude that during the past 20,000 yr much of the evolution of oceanographic change is related to the migration of the atmospheric pressure cells (the North Pacific high and Aleutian low) of the northeastern Pacific.