Collaborative Research: Rates of Long-Term Vegetation and Climate Change in North America and Europe

1980年以来化石-花粉数据变化率的分析 北美东部的许多地点经历了重大的 10，000 - 13，000年前最后一次冰川消退期间的变化， 在过去的1000年里。 PI建议扩大 对北方几个新地区的研究 半球，并确定时间，幅度， 气候和植被变化的地理格局 在过去的18,000年里， 美国参考 他们还将使用欧洲的并行数据库， 研究欧洲过去一年的变化模式和速度， 18,000年，与北美相比。 通过使用 北美和欧洲的花粉数据库，这项研究将 确定植被快速变化的程度， 环绕北方的辐射带是同步的， 从而确定可能发生重大快速变化的时间， 大气环流 此外，还将特别注意一个关键的 佛罗里达杜兰湖的站点，该站点具有连续的高分辨率 花粉地层至少可以追溯到45,000年前。 的 杜兰湖的花粉地层学显示出 变化，这可能与尚未了解的 2000年期间Dye 3格陵兰冰芯中的同位素波动 距今25000 - 55000年。 研究结果将 提供关于全球气候变化的性质和程度的重要数据， 在过去的两万年里发生了变化。

Analyses of rates of change in fossil-pollen data from eastern North America reveal that many sites experienced major changes 10,000-13,000 years ago during the last deglaciation and again during the last 1000 years. The PIs propose to expand previous research to several new regions of the northern hemisphere, and to determine the timing, magnitude, and geographic patterns of changes in climate and vegetation during the past 18,000 years in northwestern as well as eastern North America. They will also use a parallel database in Europe to study the patterns and rates of change in Europe over the last 18,000 years, for comparison with North America. Through use of pollen databases for North America and Europe, this research will establish the degree to which rapid vegetation changes in a broad band around the northern hemisphere are synchronous, and will thus identify probable times of major rapid changes in atmospheric circulation. In addition, special attention will be given to a critical site, Lake Tulane, Florida which has a continuous high-resolution pollen stratigraphy extending to at least 45,000 years ago. The pollen stratigraphy from Lake Tulane exhibits major, abrupt changes, which may correlate with as yet poorly understood isotope fluctuations in the Dye 3 Greenland ice core during the period 25,000-55,000 years ago. The results of the research will provide very important data on the nature and extent of global change in the last 20,000 years.