California Current Sensitivity to Pacific Climate: Interdecadal Changes Reconstructed From Tree Rings and Varves

Am-9509780 Berger，加州大学沃尔夫冈分校，圣地亚哥标题：加利福尼亚海流对太平洋气候的敏感性：由美国西海岸的树木年轮和各种仪器海洋和大气参数重建的年代际变化包含大量的年代际变化，但记录太短，不能在大于几年的时间尺度上分辨时间和空间细节。对20世纪70年代末北太平洋海盆气候“转换”的观测研究表明，年代际波动可能与热带太平洋有关，可能是通过厄尔尼诺和拉尼娜事件的频率和强度。了解年代际变化对于评估全球变化现象至关重要。该奖项支持一个项目，该项目使用代理记录来描述加州海流的十年到百年的变化，该记录与阿留申低/西海岸海脊复合体以及热带太平洋的冷暖事件有关。由于低频时间波动通常具有很大的空间效应，该项目将利用美国西部树木年轮年表和巴巴拉盆地不同沉积提供的上个千年的一系列替代气候记录。这项研究将澄清最近北太平洋东部的年代际变化是否反映了低频的自然变化，或者它们是否代表了一个没有相似性的独特事件。拟议的研究是一个跨学科项目，涉及斯克里普斯海洋研究所的地质研究部和气候研究部，以及亚利桑那大学树轮研究实验室。

Abstract ATM-9509780 Berger, Wolfgang University of California, San Diego Title: California Current Sensitivity to Pacific Climate: Interdecadal Changes Reconstructed From Tree Rings and Varves Instrumental oceanic and atmospheric parameters along the American West Coast contain substantial decadal variability, but the record is too short to resolve temporal and spatial details at time scales greater than a few years. Observational studies of the climate "shift" in the North Pacific basin during the late 1970's suggest that decadal fluctuations may be linked to the Tropical Pacific perhaps via the frequency and intensity of El Nino versus La Nina events. An understanding of inter-decadal variability is crucial to evaluate global change phenomena. This award supports a project using proxy records for describing the decadal-to-century variability of the California Current at it relates to the Aleutian Low/West Coast Ridge complex and to warm and cool episodes in the Tropical Pacific. Since low-frequency temporal fluctuations usually have large spatial effects, this project will exploit an array of proxy climate records for the last millennium provided by tree-ring chronologies over the Western U.S. and by varve sediments in the Barbara Basin. This study will clarify whether recent decadal changes in the eastern North Pacific are a reflection of low-frequency natural variability or whether they represent a unique episode wit no analog. The proposed research is an interdisciplinary project involving the Geological Research Division and the Climate Research Division of Scripps Institution of Oceanography, together with the Laboratory of Tree-Ring Research of the University of Arizona.