OPP-PRF: A Well-Constrained Hosing Experiment for Interrogating Arctic Precipitation Changes in the Younger Dryas

在下个世纪，降水的变化将是人为气候变化最显著的影响之一。预测未来气候变化的一个重要工具是了解过去气候是如何变化的。大约12,000年前，大量的冰冷淡水被注入北大西洋。这些淡水被认为减缓了大西洋子午线颠覆环流，这是一种对地球气候稳定至关重要的洋流。利用冰山穿过海洋的高分辨率计算机模拟结果，这项研究将检验冰山是年轻仙女木期间进入大西洋的淡水的主要贡献者的假设。这一假设将与淡水来自陆地上灾难性的洪水爆发的观点以及更传统的、低分辨率的淡水强迫模型进行对比。这些模拟将相互比较，并与年轻仙女木期间北极降水变化的记录进行比较，以促进对北极过去和现在气候变化的理解。这项研究调查了较年轻的仙女木，这是大约12,000年前发生的突然的全球气候变化的间隔。年轻的仙女木被认为是由于北大西洋增加了冷淡的水而造成的，这减缓了大西洋子午线翻转环流，尽管这种强迫的确切性质还不是很清楚。这项工作涉及使用同位素启用的全球气候模型iCESM进行敏感性实验，该模型对淡水的位置有新的限制。PI假设这些更现实的限制将产生比过去的工作更接近地质记录的气候响应。这些实验将调查这些事件的开始和持续时间，以便在年轻的仙女座上产生更完整的突然气候变化的叙述。然后，将此建模的结果与来自北极湖泊的代理记录进行比较，通过记录代理的系统的正演模拟或代理系统建模来解释。这种方法，包括对同一事件的全球气候建模、代理记录和代理系统建模，将产生对年轻仙女木气候动力学的叙述，并将这些事件与北极湖泊的沉积物联系起来。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。

In the next century, changes to precipitation will be among the most significant impacts of anthropogenic climate change. An important tool for predicting future climate change is understanding how climate has changed in the past. About 12,000 years ago, a significant volume of cold, fresh water was added to the North Atlantic. This fresh water is believed to have slowed the Atlantic Meridional Overturning Circulation, an ocean current that is important to the stability of the planet’s climate. Using the results of high-resolution computer simulations of iceberg paths through the ocean, this research will test the hypothesis that icebergs were the primary contributor of fresh water to the Atlantic during the Younger Dryas. This hypothesis will be tested against the idea that the fresh water was sourced from a catastrophic outburst flood on land, as well as against a more traditional, low-resolution model of fresh water forcing. These simulations will be compared to each other and to records of Arctic precipitation change during the Younger Dryas, advancing understanding of both past and present climate change in the Arctic. This research investigates the Younger Dryas, an interval of abrupt global climate change that occurred about 12,000 years ago. The Younger Dryas is believed to have been caused by the addition of cold, fresh water to the North Atlantic, which slowed Atlantic Meridional Overturning Circulation, though the exact nature of this forcing is not well understood. This work involves sensitivity experiments using an isotope-enabled global climate model, iCESM, with new constraints on the location of fresh water. The PI hypothesizes these more realistic constraints will produce a climate response more comparable to the geologic record than past works. These experiments will investigate the initiation and duration of these events in order to generate a more complete narrative of abrupt climate change in the Younger Dryas. The results of this modeling will then be compared to proxy records from Arctic lakes, interpreted through forward-modeling of the systems recording the proxies, or proxy system modeling. This approach, involving global climate modeling, proxy records, and proxy system modeling of the same event will produce a narrative of Younger Dryas climate dynamics and link those events to sediments from Arctic lakes.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.