Estimating and reducing the uncertainty in the future behaviour of the Greenland Ice Sheet

估计和减少格陵兰冰盖未来行为的不确定性

• 批准号: NE/F012780/1
• 金额: $ 8.2万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Training Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF012780%2F1
• 关键词: Estimating; reducing; uncertainty; future; behaviour

Sea level rise (SLR) is considered to be one of the most economically and socially important consequences of global warming. The potential contribution of the ice sheets dominates uncertainties in projections of future SLR and the fourth assessment report of the IPCC (AR4) was unable to place an upper bound on the contribution of the ice sheets because of an inadequate understanding of processes controlling their future behaviour. Uncertainties in how the climate will evolve are also important. Depending on the climate model and Greenhouse Gas (GHG) scenario the contribution from changes in the surface mass balance (SMB) of the Greenland Ice Sheet (GrIS) could range between ~0 to 4 mm/yr of SLR by 2150. For reference, the AR4 estimates that the GrIS has been contributing 0.21 mm/yr between 1993-2003. Thus, the increase in mass loss (excluding any change in ice dynamics) from Greenland over the next 150 years could go up by a factor of 20 and potentially be the largest single source of SLR but, as mentioned, the uncertainty in predicting the value is large. Further, it has been suggested that the GrIS could be eliminated by a regional temperature rise of > 4.5 degs C, with a final contribution to global SLR of some 7 m. Most simulations from the AR4 exceed this temperature threshold over Greenland by 2100. What impact climate change will have on the net mass balance of the ice sheet (i.e. on both ice dynamic and surface melt effects) and what the likely contribution will be to SLR and freshwater production remain poorly constrained. The aim of this project is to tackle several key components responsible for this uncertainty relating to how the ice sheet will respond to changing climate and what the uncertainties in the future climate are due to parameter uncertainty in the models used. In addition we will incorporate our results and the SMB model into the next generation of Hadley Centre AOGCMs.

海平面上升（SLR）被认为是全球变暖对经济和社会最重要的后果之一。冰盖的潜在贡献主导了未来 SLR 预测的不确定性，并且由于对控制冰盖未来行为的过程了解不足，IPCC 第四次评估报告（AR4）无法对冰盖的贡献设定上限。气候如何演变的不确定性也很重要。根据气候模型和温室气体 (GHG) 情景，到 2150 年，格陵兰冰盖 (GrIS) 表面质量平衡 (SMB) 变化的贡献可能在约 0 至 4 毫米/年的 SLR 范围内。作为参考，AR4 估计在 1993 年至 2003 年间，GrIS 的贡献为每年 0.21 毫米。因此，未来 150 年格陵兰岛质量损失的增加（不包括冰动力学的任何变化）可能会增加 20 倍，并可能成为 SLR 的最大单一来源，但正如前面提到的，预测该值的不确定性很大。此外，有人建议，区域温度升高 > 4.5 摄氏度可以消除 GrIS，最终对全球 SLR 的影响约为 7 m。 AR4 的大多数模拟到 2100 年都会超过格陵兰岛的这个温度阈值。气候变化将对冰盖的净质量平衡（即冰动力和表面融化效应）产生什么影响，以及对 SLR 和淡水生产的可能贡献仍然很少受到限制。该项目的目的是解决造成这种不确定性的几个关键因素，这些不确定性涉及冰盖将如何应对气候变化以及未来气候的不确定性是由于所用模型中的参数不确定性造成的。此外，我们还将把我们的结果和 SMB 模型纳入下一代哈德利中心 AOGCM 中。