Synthesizing historical records to constrain and understand Great Sea Ice Anomalies

北冰洋海冰不仅是气候变化的被动指标，也是气候变化的积极推动者。海冰、海洋和大气之间的相互作用以一种尚未完全了解的方式影响全球气候系统。该项目侧重于了解北冰洋通过弗拉姆海峡(斯瓦尔巴群岛和格陵兰岛之间)和沿东格陵兰岛海流出口海冰(大海冰异常或GSIA)的突然变化如何对北大西洋次极地产生深远和持久的影响。例如，在20世纪60年代和70年代，北冰洋的海冰和淡水突然大量涌入，导致北大西洋的盐度出现强烈异常(现已成为众所周知的大盐度异常)。有迹象表明，过去曾发生过这样的GSIA事件，但此类事件的频率、强度和原因尚不清楚。研究小组正在从1600年以来的历史和文化记录中收集数据，以确定潜在的异常情况，并将这些结果与高级建模结果相结合，以了解GSIA的潜在触发因素及其发生对北大西洋的影响。这项研究将使用多种证据，基于格陵兰岛西南部、冰岛北部和北欧西部海域附近海域长达几个世纪的海冰观测时间序列、历史和替代记录，调查大西洋北极地区突然发生的GSIA。这些数据将提供所需的经验基础，以评估全球海洋环境影响指数的发生和起源，并探讨3个假设：(1)年代际到年代际持续时间的全球气候影响指数是经常性事件，导致1960-70年代盐度异常的(次)年代际海冰异常是一种适度的实现；(2)仅从自然的内部气候系统变率就可以启动全球气候影响指数指数；(3)格陵兰岛以东的海冰异常和大西洋海表面温度的年代际变化是双向耦合的。这项研究将提供有史以来第一个一致的GSIA目录，并提高我们对大西洋北极海冰如何发生突变的基本理解。这项研究将提供重要的历史视角，有助于更好地了解北极体系的变化。这项研究具有广泛的科学意义，因为海冰出口的突然变化可能会影响北大西洋北部的海洋环流和温度、海洋生态系统和气候。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Arctic sea ice is not just a passive indicator of climate change, but also an active agent of change. Interactions between sea ice, oceans, and the atmosphere affect the global climate system in ways that are not yet fully understood. This project focuses on understanding how sudden changes in the export of sea ice (Great Sea Ice Anomalies or GSIAs) from the Arctic Ocean through Fram Strait (between Svalbard and Greenland) and along the East Greenland Current can have far-reaching and long-lasting effects in the subpolar North Atlantic. For example, in the 1960s and 1970s, a large and abrupt influx of sea ice and freshwater from the Arctic Ocean led to a strong anomaly in the salinity of the northern Atlantic Ocean (what has become known as the Great Salinity Anomaly). There are indications that such GSIA events have occurred in the past, but the frequency, intensity, and causes of such events are not yet understood. The research team is assembling data from historical and cultural records dating back to 1600 to identify potential anomalies and combining these results with advanced modelling results to understand potential triggers of GSIAs and how their occurrence affects the North Atlantic. This study will investigate abrupt GSIAs in the Atlantic Arctic using multiple lines of evidence based on data from long observational time series, historical, and proxy records of sea ice spanning several centuries in the waters near southwestern Greenland, northern Iceland, and the western Nordic Seas. These data will provide an empirical foundation required to assess the occurrence and origins of GSIAs and explore three hypotheses: (1) GSIAs of decadal to multidecadal duration are recurrent events, with the (sub)decadal sea ice anomaly leading to the 1960–70s salinity anomaly being a moderate realization; (2) GSIAs can be initiated spontaneously from natural internal climate-system variability alone; and (3) sea ice anomalies east of Greenland and multidecadal variability in Atlantic Ocean sea-surface temperatures are coupled bidirectionally. The research will provide the first-ever consistent catalog of GSIAs and improve our fundamental understanding of how abrupt changes in sea ice in the Atlantic Arctic occur. The research will provide important historical perspectives and contribute to a better understanding of changes in the Arctic system. This research has broad scientific importance because abrupt changes in sea ice export may influence ocean circulation and temperatures, marine ecosystems, and climate across the northern North Atlantic.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.