Investigating the climate feedbacks that will determine the fate of the Greenland ice sheet

海平面变化是最广泛认识到的气候变化的后果之一，由于温室气体的排放，具有潜在的严重性。自1993年以来，格陵兰岛和南极洲的极地冰盖融化对海平面变化的贡献已经使全球海平面上升了约20毫米，预计这一速度将在21世纪世纪继续增长。冰的质量损失是海平面变化预算中最不确定的部分，这主要是因为气候和冰盖模型不能很好地协同工作，这严重限制了对大冰盖如何与变化的气候相互作用进行建模的科学，该项目提议利用我们新的和独特的建模能力，对大气和冰盖相互作用的方式获得新的理解。该项目以格陵兰冰盖为重点，将研究大气、海洋和陆地表面物理学，这些物理学决定了冰上大规模表面条件变化的敏感性，以及冰的范围和高度变化如何对当地和区域气候以及大气环流产生反馈。对未来世纪的区域和全球气候模型的研究表明，对于给定的气候变化水平，有多少冰面将融化的预测可能会有两倍或更多的变化。一段时间以来，人们一直认为，由于海拔高度的降低而导致的地表变暖是预测格陵兰岛百年质量损失率的关键部分，现在看来，由于冰盖形状的变化而导致的降雪量变化可能同样重要。有几个相互作用的大气，雪面和冰流过程中涉及这些大规模的反馈，但很少有研究的现象。海洋温度在多大程度上以及以何种方式控制外流冰川的产犊率也是一个重要的未知数。该项目将使用最先进的模型，用于进行英国的全球气候预测，并与格陵兰冰盖的动态模型交互耦合。一系列实验将研究气候-冰相互作用的机制、它们与区域气候系统的联系以及它们对格陵兰冰盖的长期未来意味着什么。与此同时，观测数据（通过遥感和现场获得）将用于验证模型的能力并改进其物理参数化。

Sea level change is one of the most widely recognised and zoompotentially serious consequences of climate change due to emissions of greenhouse gases. The contribution to sea level change from melting the polar ice sheets on Greenland and Antarctica has already raised global sea levels by around 20mm since 1993, and this rate is expected to grow over the 21st century. Ice mass loss is the most uncertain part of the sea level change budget, largely because the science of modelling how large ice sheets interact with a changing climate has been severely limited by the fact that climate and ice sheet models do not work well together.This project proposes to use our new and unique modelling capabilities to gain new understanding of the ways in which the atmosphere and ice sheets interact. Focusing on the Greenland ice sheet, this project will investigate the atmospheric, ocean and land surface physics that determine the sensitivity of changing large-scale surface conditions on the ice, and how changes in ice extent and height feedback on both local and regional climate and atmospheric circulation. Studies with regional and global climate models for the coming century have shown that predictions of how much of the surface of the ice will melt ice for a given level of climate change can vary by factor of two or more. And whilst it has been appreciated for some time that warming of the surface due to its reduction in altitude as it melts is a crucial part of predicting the centennial rate of mass loss from Greenland, it now seems likely that changes in snowfall due to the changing shape of the ice sheet may be just as important. There are several interacting atmospheric, snow surface and ice flow processes involved in these large-scale feedbacks, and yet little research into the phenomena. How much, and in what way, ocean temperatures govern the calving rates of outflow glacier is also an important unknown. This project will use a state-of-the-art model, used to make the UK's global climate projections, interactively coupled to a dynamical model of the Greenland ice sheet. A series of experiments will investigate the mechanisms of climate-ice interactions, their links to the regional climate system and what they imply for the long-term future of the Greenland ice sheet. In parallel, observational data (obtained via remote sensing and in situ) will be used to both verify the model's capabilities and improve its physical parameterisations.