Ice Core Reconstruction of North Pacific Climate Variability and Environmental History from the Bona-Churchill Ice Field, Alaska

阿拉斯加博纳-丘吉尔冰原的北太平洋气候变化和环境历史的冰芯重建

• 批准号: 0099311
• 负责人: Lonnie Thompson
• 金额: $ 59.9万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0099311&HistoricalAwards=false
• 关键词: Ice; Core; Reconstruction; North; Pacific

AbstractOPP- 00-99311ThompsonThe Principal Investigators will retrieve ice cores from the col between Mt. Bona and Mt. Churchill, located in Wrangell Mountains, southeastern Alaska. The ice core records will fill a significant void in the high resolution climate history of this region and will complement and extend the tree ring-based climate records. These records will be an important contribution to the suite of high resolution ice core histories from other north polar ice fields including, Greenland, Svalbard, the High Canadian Arctic the Windy Dome Ice Cap (Franz Josef Land, Russian Arctic) and Greenland. These polar records are part of a global suite of ice core records including those retrieved from seven lower latitude, high altitude sites in Tibet, South America, and Africa. These cores have contributed critical low-latitude proxy climate histories to the continuing efforts to identify the major drivers of Quaternary climate change and to determine the global synchronicity of glacial-age climate events. Currently, there are no high quality ice core records from Alaska, so these cores should provide critical new insights. The paucity of high resolution climate histories from the northeastern side of the Pacific Basin is a major obstacle to advancing our understanding of the rapid and recent changes in the dynamic state of the Pacific region and its global connections. Of particular interest are: 1) the warming of the last 30 years that appears to be amplified at high elevations in the tropics and subtropics and in northwestern North America and northern Asia; 2) the most recent 'step' change in the dynamics of the Pacific Basin climate regime in 1976-77; and 3) the nature of recently identified multi-decadal ENSO-like mid-latitude climate variability that may have its roots in the tropical Pacific.The field program will include geophysical and surface studies designed to select the best site on the col for recovery of two high resolution, well-preserved ice core records to about 500 meters. The results from laboratory measurements of soluble and insoluble aerosol concentrations will reveal drought and wet periods and relative storm intensities. Oxygen isotope analyses should provide a proxy for the temperature history and past atmospheric circulation patterns in this area. The high annual accumulation and cold mean annual temperatures are good indicators for thick and well preserved annual signals in the physical and chemical records that will allow excellent time control with annual resolution for the last 1000 years. The complete record should extend back at least 5,000 years. The significance of recent climatic and environmental variations must be evaluated from a perspective provided by a globally dispersed, long-term proxy climate records. Linking these records from pole to pole allows assessment of the global nature of these climatic variations and identification of critical linkages between the higher latitudes and the tropics where changes in the global heat source can trigger global-scale changes in the climate system.

主要研究人员将从珠穆朗玛峰和珠穆朗玛峰之间的山坳中取回冰芯。 博纳和Mt. 丘吉尔，位于阿拉斯加东南部的兰格尔山脉。 冰芯记录将填补该地区高分辨率气候历史的一个重要空白，并将补充和扩展基于树木年轮的气候记录。这些记录将是一个重要的贡献，从其他北极冰原，包括格陵兰岛，斯瓦尔巴特群岛，加拿大北极的风穹冰帽（弗朗茨约瑟夫地，俄罗斯北极）和格陵兰岛的高分辨率冰芯历史套件。 这些极地记录是全球冰芯记录套件的一部分，包括从西藏，南美洲和非洲的七个低纬度高海拔地点检索的冰芯记录。 这些岩心为确定第四纪气候变化的主要驱动因素和确定冰期气候事件的全球同步性的持续努力提供了关键的低纬度代用气候历史。目前，阿拉斯加没有高质量的冰芯记录，因此这些冰芯应该提供关键的新见解。 太平洋盆地东北侧高分辨率气候历史的缺乏是我们理解太平洋地区及其全球联系动态的快速和近期变化的一个主要障碍。 特别令人感兴趣的是：1）过去30年的变暖在热带和亚热带地区以及北美西北部和北方亚洲的高海拔地区似乎被放大了; 2）1976-77年太平洋盆地气候动态的最新“阶跃”变化;和3）最近确定的多年代际ENSO中期的性质，纬度气候变化，可能有其根源在热带太平洋。实地计划将包括地球物理和表面研究，旨在选择最好的网站上的山坳恢复两个高分辨率，保存完好的冰芯记录到大约500米。 可溶性和不溶性气溶胶浓度的实验室测量结果将揭示干旱和潮湿时期以及相对风暴强度。 氧同位素分析应提供一个代理的温度历史和过去的大气环流模式在这个地区。 高的年积累和寒冷的年平均温度是物理和化学记录中保存完好的厚年度信号的良好指标，这将允许在过去1000年中以年度分辨率进行出色的时间控制。完整的记录至少可以追溯到5,000年前。最近的气候和环境变化的重要性必须从全球分散的长期代用气候记录的角度进行评估。将这些记录从一个极点连接到另一个极点，可以评估这些气候变化的全球性质，并确定高纬度和热带地区之间的关键联系，在这些地区，全球热源的变化可以引发气候系统的全球范围的变化。