Late Quaternary Climate Change Across Northern Alaska: A Comparison of Lake-Level and Pollen Variations

题目：阿拉斯加北部晚第四纪气候变化：湖位和花粉变化的比较本研究项目将利用湖位记录作为有效湿度的代用物，研究阿拉斯加北部晚第四纪（距今21000年）的古气候问题和假设。气候模式模拟的结果和概念性古气候情景提供的假设可以对照地质记录进行检验。其他问题则来自古植被记录的区域变化，需要气候解释。具体的古气候问题有：1)在晚冰期和全新世期间，阿拉斯加北部的有效湿度是否存在东西梯度？ 2)与晚冰期环流变化相关的有效湿度主要增加是在什么时候发生的？ 3)在11000 -6000年（校准）BP期间，当温度可能比现在更高时，降水是增加还是减少？ 4)记录中是否存在其他快速的区域性有效湿度变化？本研究的主要贡献将是：(1)区域古水文的经验数据；(2)根据古水文和其他古气候数据评估植被和陆地系统其他因子（如风成过程和流域地球化学）的变化。

Abstract ATM-9500906 Finney, Bruce University of Alaska Title: Late Quaternary Climate Change Across Northern Alaska: A Comparison of Lake-Level and Pollen Variations This research project will address paleoclimatic questions and hypotheses for northern Alaska during the late-Quaternary (21,000 yr BP to present) using lake-level records as proxies for effective moisture. Results of climate model simulations and conceptual paleoclimate scenarios provide hypotheses to be tested against the geologic record. Other questions are derived from regional changes in the paleovegetational record that require climatic explanations. Specific paleoclimatic questions are: 1) was there an east-west gradient in effective moisture across northern Alaska during the late glacial as well as the Holocene, 2) when did the major increase in effective moisture related to late-glacial circulation changes occur, 3) was precipitation either enhanced or reduced during the period 11,000-6000 (calibrated) yr BP, when temperatures were probably warmer that present, and 4) are there other rapid, regional effective moisture changes in the record? The major contributions of this research will be 1) empirical data on regional paleohydrology, and 2) an assessment of changes in vegetation and other factors of the terrestrial system (e.g., eolian processes and watershed geochemistry) in the light of the paleohydrologic and other paleoclimatic data.