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

在下一个世纪，降水量的变化将是人类气候变化的最重要影响之一。预测未来气候变化的一个重要工具是了解过去气候如何变化。大约12，000年前，大量寒冷的淡水被添加到北大西洋。这些淡水被认为减缓了大西洋经向翻转环流，这是一种对地球气候稳定至关重要的洋流。利用高分辨率计算机模拟冰山在海洋中的路径的结果，这项研究将测试冰山是新仙女木时期大西洋淡水的主要贡献者的假设。这一假设将被测试的想法，淡水是来自一个灾难性的突发洪水在陆地上，以及对一个更传统的，低分辨率的淡水强迫模型。这些模拟将相互比较，并与新仙女木时期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。这项研究调查了新仙女木，这是大约12,000年前发生的全球气候突然变化的间隔。新仙女木事件被认为是由于北大西洋增加了冷的淡水，减缓了大西洋经向翻转环流，尽管这种强迫的确切性质还没有得到很好的理解。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，并对淡水的位置进行了新的限制。PI假设这些更现实的限制将产生比过去的作品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，以产生一个更完整的叙述在新仙女木气候突变。然后将此建模的结果与北极湖泊的代理记录进行比较，通过记录代理的系统的前向建模或代理系统建模进行解释。这种方法，涉及全球气候建模，代理记录，和代理系统建模的同一事件将产生一个叙述新仙女木气候动力学和连接这些事件的沉积物从北极lakes.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

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.