Collaborative Research: A Synthesis of Rapid Meltwater and Ice Discharge Changes: Large Forcings from the Ice with Impacts on Global Sea Level and North Atlantic Freshwater Budgets

格陵兰冰盖的淡水排放对全球海平面有直接和直接的影响，有可能通过干扰附近海洋深水形成的敏感区域来影响全球气候，并且是泛北极水平衡的一个重要但尚未被量化的部分。研究人员将使用多种方法综合一系列现有的数据集。通过地表数据校准的遥感和大气模拟准确地揭示了格陵兰岛几十年来地表融化的空间解析历史，沿海气象站将观测扩展到一个多世纪。复杂的传输技术，包括非线性方法，将被用于从这些仪器数据缩小到具体的冰芯融化记录，了解广泛的信号是如何被存档的。由此得出的传递函数、长达几个世纪的冰芯记录和长达一个世纪的海岸站记录将使我们能够在比现在更长的时间内确定融水的变化。遥感得到的冰架/冰舌和冰川出口流速的变化将与同期的地表融化历史相结合，并使用包含纵向应力的诊断冰流模型进行分析，以了解融水变异性和冰架变化如何影响冰流变异性。如果诊断成功，那么来自冰芯的更长的融化历史可以用来估计相同间隔内冰流的变化；冰流和融水变化之间的关系也可用于预测未来影响淡水通量的冰盖变化。

AbstractFreshwater discharge from the Greenland ice sheet has a direct and immediate effect on global sea level, has the potential to impact global climate by perturbing nearby sensitive regions of oceanic deep-water formation, and is an important but as yet poorly quantified part of the pan-Arctic water balance. The investigators will synthesize a range of extant data sets using numerous methods. Remote sensing and atmospheric modeling calibrated by surface data accurately reveal a spatially resolved history of surface melting on Greenland over decades, and coastal weather stations extend observations to more than a century. Sophisticated transfer techniques, including nonlinear approaches, will be used to downscale from these instrumental data to specific ice-core records of melt, learning how the widespread signal is archived. The derived transfer functions, the centuries-long ice-core records, and the century-length coastal-station records then will allow upscaling to determine meltwater variability over longer times than now available. Remotely sensed changes in ice shelves/tongues and outlet-glacier flow speeds will be combined with the contemporaneous histories of surface melting, and analyzed using diagnostic ice-flow modeling incorporating longitudinal stresses to learn how meltwater variability and ice shelf changes force ice-flow variability. If successful diagnosis is achieved, then the longer melt history from the ice-cores can be used to estimate the ice-flow variability over the same interval; the relations between ice-flow and melt changes also can be used prognostically in assessing future changes in the ice sheet affecting freshwater fluxes.