Collaborative Research: Improving estimates of Greenland’s freshwater flux: Where do icebergs form and where do they melt?

合作研究：改进对格陵兰岛淡水通量的估计：冰山在哪里形成以及在哪里融化？

• 批准号: 2052549
• 负责人: Dustin Carroll
• 金额: $ 5.61万
• 依托单位: San Jose State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2052549&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; estimates; Greenland

Greenland is a large reservoir of fresh, frozen water that flows downhill until it reaches the ocean. Some of this frozen reservoir melts at the surface and directly enters the ocean. Some of the ice instead breaks off, making icebergs that melt as they float around the ocean like ice cubes in a glass of water. Where and when this freshwater enters the ocean can influence the ocean currents that carry heat, salt, and vital nutrients for marine life. However, we cannot tell if recent changes to the amount of Greenland ice that is melted and mixed into the ocean are important because we don’t yet have accurate maps of where exactly this freshwater enters the ocean. In this project, we will combine 1) photos of Greenland’s coastline taken from satellites and 2) measurements of the warm, salty, and fast coastal waters taken from ships and instruments in the ocean. From these observations we will create new maps of how much Greenland icebergs melted from 2010 to 2023. Our science team will develop outreach activities that focus on iceberg melting and will work with an artist to educate the public about the importance of iceberg melt and inspire them to think more about the Earth’s fascinating icy features. Increasing freshwater flux from the Greenland Ice Sheet influences ocean properties, with potentially large consequences for circulation, marine ecosystems, and climate at local-to-global scales. The severity of the downstream effects depends on: the fingerprint of meltwater runoff from the ice-sheet surface, meltwater produced where the ice sheet flows into the relatively warm and salty ocean, and meltwater injected into the ocean by the gradual decay of icebergs. Variations in freshwater produced by iceberg melt are poorly mapped and yet may be incredibly important since icebergs can transport cold, fresh meltwater far from the ice-sheet margins to remote ocean basins. In this project, we will combine independent iceberg melt rate estimation methods using satellite and ocean observations. We will investigate the drivers of iceberg melt and also quantify potential errors and the uncertainty in each of our methods. We will pair the iceberg melt rate estimates with observations of iceberg production from the Greenland Ice Sheet to construct time series of iceberg freshwater flux from 2010 to 2023. The project will yield time series of iceberg meltwater flux maps and determine how iceberg meltwater compares to other freshwater sources, such as surface and subglacial meltwater runoff from the ice sheet. We will also produce several novel datasets (e.g., spatially distributed iceberg size distributions, melt rates, and freshwater flux time series) that will be valuable for studies focused on ice sheet-ocean interactions. We will incorporate data products produced by the project into the open-source QGreenland geographic information system package as part of efforts to increase data accessibility and use. The project also provides an opportunity for two female early career scientists to strengthen their research programs, and we will emphasize recruitment of underrepresented groups for junior personnel. Finally, the project team will develop K–12 outreach activities that demonstrate iceberg melting in a fish-tank fjord and will work with an artist who has experience in creatively disseminating polar research to a broad range of audiences; this will enable us to communicate our project findings more effectively to the public.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.

格陵兰岛是一个巨大的淡水冰冻水库，这些冰冻水库中的一些在表面融化并直接进入海洋，导致冰山在漂浮时融化。就像一杯水中的冰块一样，淡水进入海洋的地点和时间会影响为海洋生物输送热量、盐和重要营养物质的洋流。然而，我们无法判断格陵兰岛的数量最近是否发生了变化。融化的冰和混合到海洋中的水很重要，因为我们还没有准确的淡水进入海洋位置的地图，在这个项目中，我们将 1) 从卫星拍摄的格陵兰岛海岸线照片和 2) 温暖、咸水和海水的测量。根据这些观测结果，我们将绘制 2010 年至 2023 年格陵兰岛冰山融化程度的新地图。我们的科学团队将开展以冰山融化为重点的外展活动。并将与一位艺术家合作，向公众宣传冰山融化的重要性，并激发他们更多地思考地球迷人的冰特征。格陵兰冰盖淡水通量的增​​加会影响海洋特性，对循环和海洋生态系统可能产生重大影响。以及局部到全球范围内的气候影响的严重程度取决于：冰盖表面融水径流的指纹、冰盖流入相对温暖和咸的海洋时产生的融水以及融水。冰山融化产生的淡水变化虽然很难绘制出来，但可能非常重要，因为在这个项目中，冰山可以将寒冷的新鲜融水从冰盖边缘输送到遥远的海洋盆地。 ，我们将利用卫星和海洋观测结合独立的冰山融化速率估计方法，我们将研究冰山融化的驱动因素，并量化每种方法的潜在误差和不确定性，我们将冰山融化速率估计与冰山观测相结合。生产从格陵兰冰盖构建2010年至2023年冰山淡水通量时间序列。该项目将生成冰山融水通量图的时间序列，并确定冰山融水与其他淡水来源（例如来自冰的地表和冰下融水径流）的比较我们还将生成几个新颖的数据集（例如，空间分布的冰山尺寸分布、融化速率和淡水通量时间序列），这些数据集对于关注冰的研究非常有价值。我们将把该项目产生的数据产品纳入开源 QGreenland 地理信息系统包中，作为增加数据可访问性和使用的努力的一部分，该项目还为两名早期职业科学家提供了一个加强其能力的机会。最后，项目团队将开展 K-12 外展活动，展示鱼缸峡湾中的冰山融化，并将与一位具有创造性传播极地经验的艺术家合作。研究到一个广泛的受众；这将使我们能够更有效地向公众传达我们的项目成果。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。