East Antartic ice sheet and ocean interactions during past warmer than present climates

过去气候比现在温暖时东南南极冰盖和海洋的相互作用

• 批准号: EP/X02623X/1
• 负责人: Tina Van De Flierdt
• 金额: $ 26万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX02623X%2F1
• 关键词: East; Antartic; ice; sheet; ocean

The recently published Sixth Assessment Report by the Intergovernmental Panel on Climate Change identified the Antarctica's contribution to sea-level change as the single greatest uncertainty in global climate predictions for the coming decades and centuries, and the highest priority issue facing climate change science. Observations show that ice sheets grounded on land below current sea level (marine-based ice sheets) are vulnerable to ocean-induced basal melting, resulting in destabilization and sea level rise. However, the exact mechanisms that drive oceanic heat exchange across the continental shelves, and their influence on the stability of the marine-based ice sheets are poorly known. High-resolution records of past ice sheet and ocean circulation interaction can fill this gap. Of particular use is the study of past warmer-than-present climate intervals, when temperatures and CO2 concentrations were similar to the present-day or those projected for the end of this century. The ICEAN project will deliver a unique shelf to open ocean transect of geological records on water masses, ocean temperature, and ice sheet position for the Mid-Pliocene warm period (~3 million years ago). Back then, atmospheric CO2 concentrations where similar to the present-day (ca. 400ppm), and mean annual surface temperatures were ca. 1.8-3.6C warmer than preindustrial values. These conditions led to reduced ice sheet extent and increased sea levels. The data produced in the ICEAN project will for the first time allow to constrain processes and drivers for ice retreat during the Mid-Pliocene warm period in a critical location off East Antarctica. The results will be key to validate and test current ice sheet models, which are used to project future seal level rise.

政府间气候变化专门委员会最近发布的第六次评估报告指出，南极洲对海平面变化的影响是未来几十年和几个世纪全球气候预测中最大的不确定性，也是气候变化科学面临的最优先问题。观测表明，当前海平面以下陆地上的冰盖（海洋冰盖）很容易受到海洋引起的基底融化的影响，从而导致不稳定和海平面上升。然而，驱动跨大陆架海洋热交换的确切机制及其对海洋冰盖稳定性的影响却鲜为人知。过去冰盖和海洋环流相互作用的高分辨率记录可以填补这一空白。特别有用的是对过去比现在温暖的气候区间的研究，当时的气温和二氧化碳浓度与现在或本世纪末的预测相似。 ICEAN 项目将提供一个独特的大陆架，以开放海洋横断面，记录上新世中期温暖期（约 300 万年前）的水团、海洋温度和冰盖位置的地质记录。当时，大气中二氧化碳浓度与现在相似（约 400 ppm），年平均地表温度约为 100 ppm。比工业化前温度高 1.8-3.6℃。这些条件导致冰盖范围缩小和海平面上升。 ICEAN项目产生的数据将首次能够限制南极洲东部关键地区上新世中期温暖时期冰退缩的过程和驱动因素。结果将是验证和测试当前冰盖模型的关键，该模型用于预测未来海平面上升。