Sea Ice and Westerly winds during the Holocene in coastal Antarctica, to better constrain oceanic CO2 uptake

南极洲沿海全新世期间的海冰和西风，以更好地限制海洋二氧化碳的吸收

• 批准号: NE/W001535/1
• 负责人: Elizabeth Thomas
• 金额: $ 108.33万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FW001535%2F1
• 关键词: Sea; Ice; Westerly; winds; during

The Southern Ocean represents less than one-tenth of the area of the global ocean, yet it currently absorbs 43% of the total anthropogenic CO2 and 75% of the heat. Critically, the Southern Ocean's capacity to modulate the atmospheric CO2 concentration is governed by the strength and position of the Southern Hemisphere westerly winds. These winds drive upwelling of carbon-rich deep water, which together with sea ice coverage, determines the ocean surface area available for air-sea gas exchange. Westerly winds are predicted to increase in strength during the 21st century, as a result of anthropogenic forcing, while sea ice is predicted to decrease. The combination of stronger winds over the surface ocean and reduced sea ice cover will enhance upwelling of carbon-rich water from the deep ocean. Thus, the Southern Ocean may switch from a CO2 sink to a CO2 source, potentially releasing CO2 into the atmosphere and accelerating global warming through enhanced radiative forcing.However, our understanding of the role of westerly winds on CO2 release is limited by the short observational records with large uncertainties in the magnitude of projected westerly wind changes in climate models. In order to better constrain future predictions of CO2 emissions and climate change, we urgently require long records of atmospheric CO2, westerly winds and sea ice in the Southern Ocean. Ice cores are the only paleoclimate archive that can reconstruct all three parameters beyond the instrumental period. The aim of this proposal is to provide high resolution records of westerly winds, sea ice and atmospheric CO2 concentrations over multi-decadal to millennial timescales. We will do this by drilling a new ice core in coastal Antarctica, match funded by the National Centre for Polar and Oceanographic Research (NCPOR), Indian Ministry of Earth Science, with additional support secured from the Norwegian Polar Institute and the UK embassy in Delhi. We will conduct state-of-the-art analysis, using newly developed proxies for westerly winds based on marine diatoms. Advanced measurement of the stable isotopic composition of CO2 will take place in the newly established UK Relic Air Extraction and Gas Analysis System (UK RArE-GAS) laboratories and build on the UK's growing expertise in this field.This is an exciting opportunity for UK scientists to collaborate with leading polar research institutes in Norway and India. This tri-national partnership (India/Norway/UK) considerably increases the scientific, societal, and political impact. Disentangling the drivers of CO2 variability over seasonal to millennial scales is essential in predicting future changes in atmospheric CO2 concentrations. If the Southern Ocean switches from a CO2 sink, removing anthropogenic CO2 from the atmosphere, to a CO2 source, releasing CO2 from the deep ocean, is of global concern. Thus, we anticipate this project will have high scientific, political, and social-economic impacts.These social-economic impacts will hit some countries harder than others. India's large coastline and rapidly increasing population, many of whom live in low-lying coastal basins, make it particularly susceptible to future sea level rise. India is the fifth most vulnerable country in the world to the impacts of climate change and is under pressure to reduce its greenhouse gas emissions. Thus, this new collaboration with partners in India provides compelling potential for NERC and UK scientists to support and promote climate science in an ODA country. Working directly with the Indian Ministry of Earth Sciences and facilitated by ongoing collaborations with senior advisor for climate change and environment at the British High Commission in Delhi.

南大洋仅占全球海洋面积的不到十分之一，但目前却吸收了人为二氧化碳总量的 43% 和 75% 的热量。至关重要的是，南大洋调节大气二氧化碳浓度的能力取决于南半球西风的强度和位置。这些风推动富含碳的深水上升，再加上海冰覆盖，决定了可用于空气-海洋气体交换的海洋表面积。由于人为强迫，预计 21 世纪西风强度将增强，而海冰预计将减少。表层海洋上的强风和海冰覆盖面积的减少相结合，将增强深海中富含碳的水的上涌。因此，南大洋可能从二氧化碳汇转变为二氧化碳源，有可能将二氧化碳释放到大气中，并通过增强的辐射强迫加速全球变暖。然而，我们对西风对二氧化碳释放的作用的理解受到短期观测的限制。气候模型中预测的西风变化幅度具有很大不确定性的记录。为了更好地限制未来对二氧化碳排放和气候变化的预测，我们迫切需要大气二氧化碳、西风和南大洋海冰的长期记录。冰芯是唯一能够重建工具作用时期以外的所有三个参数的古气候档案。该提案的目的是提供数十年至千年时间尺度的西风、海冰和大气二氧化碳浓度的高分辨率记录。我们将通过在南极洲沿海钻探一个新的冰芯来实现这一目标，该项目由国家极地和海洋研究中心（NCPOR）、印度地球科学部资助，并得到挪威极地研究所和英国驻德里大使馆的额外支持。我们将使用基于海洋硅藻的新开发的西风代理进行最先进的分析。二氧化碳稳定同位素组成的高级测量将在新成立的英国遗迹空气提取和气体分析系统 (UK RArE-GAS) 实验室中进行，并以英国在该领域不断增长的专业知识为基础。这对英国科学家来说是一个令人兴奋的机会与挪威和印度领先的极地研究机构合作。这种三国伙伴关系（印度/挪威/英国）大大增加了科学、社会和政治影响。理清季节性到千禧年范围内二氧化碳变化的驱动因素对于预测未来大气二氧化碳浓度的变化至关重要。如果南大洋从二氧化碳汇（从大气中去除人为二氧化碳）转变为二氧化碳源（从深海释放二氧化碳），就会引起全球关注。因此，我们预计该项目将产生重大的科学、政治和社会经济影响。这些社会经济影响对一些国家的打击将比其他国家更大。印度漫长的海岸线和快速增长的人口（其中许多人生活在低洼的沿海盆地）使其特别容易受到未来海平面上升的影响。印度是世界上第五个最容易受到气候变化影响的国家，面临着减少温室气体排放的压力。因此，与印度合作伙伴的这一新合作为 NERC 和英国科学家在官方发展援助国家支持和促进气候科学提供了巨大的潜力。直接与印度地球科学部合作，并通过与德里英国高级专员公署气候变化和环境高级顾问的持续合作来促进。

项目成果

1000 years of climate history from a coastal West Antarctic ice core site

南极西部沿海冰芯遗址 1000 年的气候历史

• DOI: http://dx.10.5194/egusphere-egu22-5914
• 发表时间: 2022
• 作者: Rowell I

New ice core proxy for reconstructing past wind variability in the Atlantic sector of the Southern Hemisphere Westerly Wind belt

用于重建南半球西风带大西洋部分过去风变率的新冰芯代理

• DOI: http://dx.10.5194/egusphere-egu23-10308
• 发表时间: 2023
• 作者: Tetzner D

Diatoms in Ice Cores, a novel proxy for reconstructing past wind variability in the Pacific sector of the Southern Hemisphere Westerly Wind belt

冰芯中的硅藻，重建南半球西风带太平洋地区过去风变率的新代理

• DOI: http://dx.10.5194/egusphere-egu22-10952
• 发表时间: 2022
• 作者: Tetzner D

Timing of the recent migration and intensification of the Southern Hemisphere westerly winds

南半球西风近期迁移和加强的时间

• DOI: http://dx.10.21203/rs.3.rs-2743347/v1
• 发表时间: 2023
• 作者: Tetzner D