GLobal glacIer maSs balance prediction on SeAsonal and DEcadal scale (GLISSADE)

冰川提供重要的水资源，对区域供水至关重要。正在进行的气候驱动的冰川消退影响了冰川集水区的水供应，并促进了全球海平面的上升。该项目旨在阐明冰川质量平衡(即冰和雪的净增减)在季节性(即6个月的提前期)和十年(即数年的提前期)时间尺度上的可预测性。为了实现这一点，基于追溯气候模型的季节和年代际预报(CFSv2、GloSea5、DePreSys)被用作基于过程的全球冰川流动动力学模型(OGGM)的强迫数据。回溯性预报是使用当今最先进的大气-海洋-气候耦合模式和过去每个预测期的有效初始条件计算出的过去一段时间的预报。这种方法允许将预测状态与过去的相应观测状态(例如冰川质量平衡和冰川长度时间序列)进行比较。这样，就可以为全世界的冰川详细研究关于季节尺度上的冰川质量平衡和十年尺度上的冰川长度变化的季节和十年预测技巧，并与气候系统的特征相关。因此，该项目有助于提高我们对冰川可预测性的了解，并可作为未来冰川预报系统的基础。这对于提供可靠的水资源供应和海平面上升预测尤其重要。

Glaciers provide important water resources and are essential to regional water supply. The ongoing climate-driven glacier retreat affects water availability in glacierized watersheds and contributes to global sea level rise. This project pursues the goal to shed light on the predictability of glacier mass balances (i.e. the net gain or loss of ice and snow) on seasonal (i.e. lead time of 6 months) and decadal (i.e. lead time of several years) time-scales. To achieve this, retrospective climate model-based seasonal and decadal forecasts (CFSv2, GloSea5, DePreSys) are used as forcing data for a process-based global glacier model with ice flow dynamics (OGGM). Retrospective forecasts are forecasts computed for past periods of time using both today’s state of the art coupled atmosphere-ocean-climate models and valid initial conditions for each forecast period in the past. This approach allows for comparing forecasted states with corresponding observed states from the past (e.g. glacier mass balances and glacier length time series). In this way, the skill of seasonal and decadal predictions regarding glacier mass balances on the seasonal scale and changes in glacier length on the decadal scale can be studied in detail for glaciers worldwide and related to features in the climate system. Thus, the project contributes to improve our knowledge about the predictability of glaciers and might serve as a basis for future glacier forecast systems. This is especially relevant for providing reliable forecasts of water availability and sea level rise.