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.

南大洋面积不到全球海洋面积的十分之一，但它目前吸收了人类活动产生的二氧化碳总量的43%和热量的75%。重要的是，南大洋调节大气CO2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涌上，与海冰覆盖一起，决定了可用于海气交换的海洋表面积。由于人类活动的影响，预计在世纪西风的强度将增加，而海冰预计将减少。海面上的强风和海冰覆盖的减少将加强深海富碳水的上涌。因此，南大洋可能会从一个CO2汇转换为一个CO2源，潜在地将CO2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CO2释放的作用的理解是有限的，因为观测记录很短，气候模式中预测的西风变化幅度存在很大的不确定性。为了更好地限制未来对二氧化碳排放和气候变化的预测，我们迫切需要对南大洋的大气二氧化碳、西风和海冰进行长期记录。冰芯是唯一可以重建仪器时期以外所有三个参数的古气候档案。这项建议的目的是提供高分辨率的记录西风，海冰和大气CO2浓度在几十年到千年的时间尺度。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，该项目由印度地球科学部国家极地和海洋学研究中心（NCPOR）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。我们将进行最先进的分析，使用新开发的基于海洋硅藻的西风代理。新成立的英国遗迹空气提取和气体分析系统（UK RArE-GAS）实验室将对二氧化碳的稳定同位素组成进行先进的测量，并建立在英国在这一领域不断增长的专业知识基础上。这对英国科学家来说是一个令人兴奋的机会，可以与挪威和印度的领先极地研究机构合作。这种三国合作伙伴关系（印度/挪威/英国）大大增加了科学，社会和政治影响。解开季节到千年尺度的CO2变化的驱动因素对于预测大气CO2浓度的未来变化至关重要。如果南大洋从一个CO2汇（从大气中清除人为CO2）转变为一个CO2源（从深海释放CO2），将引起全球关注。因此，我们预计该项目将产生很大的科学、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。印度拥有广阔的海岸线，人口迅速增加，其中许多人生活在低洼的沿海盆地，这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，并面临减少温室气体排放的压力。因此，与印度合作伙伴的这种新合作为NERC和英国科学家在ODA国家支持和促进气候科学提供了令人信服的潜力。直接与印度地球科学部合作，并通过与德里英国高级委员会气候变化和环境高级顾问的持续合作提供便利。

项目成果

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: 10.5194/egusphere-egu23-10308
• 发表时间: 2023
• 作者: Tetzner D

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: 10.5194/egusphere-egu22-5914
• 发表时间: 2022
• 作者: Rowell I

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