Long-Term Variations of the North Atlantic Oscillation

该奖项支持一个研究项目，该项目旨在利用摩洛哥的树木年轮数据、西欧和北美东部的适当树木年轮数据、海冰范围记录和GISP2格陵兰冰芯的指数来提供1000年北大西洋涛动(NAO)的重建记录。以往的研究表明，北大西洋副热带高压和副极地低压地区之间的冷季大尺度大气质量变化与摩洛哥降水高度相关。由于摩洛哥在物理上位于NAO系统的南端，该系统中的微小扰动被记录在摩洛哥的降水记录中。树木年轮通过相关大气水汽输送方向的变化记录了NAO状态的变化。西欧和北美东部的三环数据以及格陵兰冰芯数据和区域海冰范围也显示出对NAO状态的高度响应，因此，可以用来评估振荡的更北端。NAO指数的树轮结构将把近期的NAO趋势放在一个长期的视角中。特别令人感兴趣的是将最近的NAO趋势与小冰期和其他气候极端时期的NAO变化进行比较。该项目的最终成果将是长期天气气候学，显示NAO的各种状态及其相关的北大西洋天气条件和北大西洋海温距平场。

Abstract ATM-9615678 Stockton, Charles W. University of Arizona Title: Long-Term Variations of the North Atlantic Oscillation This award supports a research project designed to use tree-ring data from Morocco, appropriate tree-ring data from western Europe and eastern North America, sea ice extent records, and indices from the GISP2 Greenland ice cores to provide a 1000 year reconstructed record of variability of the North Atlantic Oscillation (NAO). Previous investigations have shown that the cool season large scale alternations of atmospheric mass between the North Atlantic regions of subtropical high pressure and subpolar low pressure are highly correlated with precipitation in Morocco. Because Morocco is physically located at the southern extremity of the NAO system, slight perturbations in the system are recorded in the Moroccan precipitation records. The tree rings record variations in the state of the NAO through the changing direction of associated atmospheric moisture transport. Three-ring data from western Europe and eastern North America, as well as Greenland ice core data and regional sea ice extent also show a high degree of response to the state of the NAO, and thus, can be used to assess the more northern extremity of the oscillation. The tree-ring construction of the NAO index will place recent NAO trends in a long-term perspective. Of particular interest is comparison of the recent NAO trend with NAO variations during the Little Ice Age and other periods of climate extreme. A final product of the project will be a long-term synoptic climatology showing various states of the NAO along with their associated North Atlantic synoptic weather conditions and North Atlantic SST anomaly fields.