Collaborative Research: Refreezing in the firn of the Greenland ice sheet: Spatiotemporal variability and implications for ice sheet mass balance

合作研究：格陵兰冰盖冰层的重新冻结：时空变化及其对冰盖质量平衡的影响

• 批准号: 1603331
• 负责人: Marco Tedesco
• 金额: $ 31.87万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1603331&HistoricalAwards=false
• 关键词: Collaborative; Research; Refreezing; firn; Greenland

The Arctic is warming and the Greenland ice sheet is melting. In total, the ice sheet stores enough water to raise sea level by approximately 6 meters. However, how surface meltwater generated in the summer makes its way from its location on the ice sheet to the ocean is not well understood. Two competing but not mutually exclusive theories are 1) the meltwater percolates into the ice sheet pores and is stored for a relatively long time. 2) The initial infiltrating meltwater refreezes at shallow depth in the firm, forming a hard pan that prohibits further infiltration. In this latter case, the meltwater quickly moves downslope along the surface of the ice sheet until it drains into the ocean. Rennermalm will test these hypotheses through a combination of field work, remote sensing from satellites, and modeling. Moreover, Rennermalm believes that during the most recent warming, the shallow refreezing mechanism has been playing a lesser role in the delivery of meltwater to the ocean than in previous times. To explore this hypothesis Rennermalm will compare the physical characteristics of modern cores with those extracted from earlier expeditions.The project will involve graduate and undergraduate student training. The PI?s will collaborate with the Rutgers Film Bureau to ensure effective communication with the public. The PI?s expect that the Rutgers Film Bureau director will seek to showcase the documentary at film festivals and other venues. In year one, two Rutgers Film Bureau members (the director and one student) will travel to Greenland to capture the day-to-day choices of scientific research in an extreme environment and produce a short multimedia narrative. Sea level is expected to rise in the decades to come, partially due to the melting of the Greenland ice sheet. However, we do not fully understand how meltwater generated on the surface of the ice sheet makes its way to the ocean. One line of thinking is that surface meltwater makes its way into the porous ice sheet where it is stored, either refrozen or in a liquid state, for relatively long times. Alternatively, as proposed by these investigators, the first seasonal meltwater that makes its way into the shallow ice, refreezes and blocks further infiltration, resulting in water that quickly moves down the surface ice sheet until it enters the ocean. Knowing the fate of meltwater is imperative if we are to understand how fast sea level will rise in the future. These investigators will integrate field work, computer modeling, and analyze data from satellites.

北极正在变暖，格陵兰冰盖正在融化。 总的来说，冰盖储存的水足以使海平面上升约6米。 然而，夏季产生的表面融水如何从冰盖上的位置进入海洋还不清楚。 两个相互竞争但不相互排斥的理论是：1）融水进入冰盖孔隙，并储存了相对较长的时间。 2)最初渗透的融水在公司的浅深度重新冻结，形成一个坚硬的平底锅，阻止进一步渗透。 在后一种情况下，融水会沿着冰盖表面沿着迅速向下移动，直到流入海洋。 Rennermalm将通过实地工作、卫星遥感和建模相结合来测试这些假设。 此外，Rennermalm认为，在最近的变暖过程中，浅层再冻结机制在向海洋输送融水方面所起的作用比以前要小。为了探索这一假设，Rennermalm将把现代岩芯的物理特征与早期考察中提取的岩芯进行比较。该项目将涉及研究生和本科生的培训。 私家侦探？s将与罗格斯电影局合作，以确保与公众的有效沟通。 私家侦探？我们预计罗格斯大学电影局局长将寻求在电影节和其他场所展示这部纪录片。在第一年，罗格斯大学电影局的两名成员（导演和一名学生）将前往格陵兰岛，在极端环境中捕捉科学研究的日常选择，并制作一个简短的多媒体叙事。预计未来几十年海平面将上升，部分原因是格陵兰冰盖的融化。 然而，我们并不完全了解冰盖表面产生的融水如何进入海洋。 一种思路是，表面融水进入多孔冰盖，在那里它被储存，无论是重新冻结或以液体状态，相对较长的时间。 或者，正如这些研究人员所提出的那样，第一次进入浅冰的季节性融水重新冻结并阻止进一步渗透，导致水迅速沿着冰盖表面向下移动，直到进入海洋。 如果我们想了解未来海平面上升的速度，了解融水的命运是必不可少的。 这些研究人员将整合实地工作、计算机建模和分析卫星数据。