冰盖质量变化与全球气候变化密切相关，直接影响海平面的变化，甚至对局部沿海地区人类生活造成重大影响。由于冰盖位于极寒之地，实地观测资料缺乏，准确估计其质量变化以了解其当前状态、预测其未来的演化以及评估其对海平面变化的贡献等仍然充满了挑战。因此，本项目拟联合卫星重力与多代测高卫星数据精化冰雪密度，并改进卫星测高数据以揭示冰盖近18年的质量变化规律。主要研究内容为：1)发展改进的重复轨迹算法，利用多代卫星测高数据获取连续的冰盖高度变化；2)联合卫星重力与卫星测高数据精化冰雪密度；3)改进卫星测高数据，获取长时段、连续的冰盖质量变化，并评估冰雪密度不确定度对冰盖质量变化的影响以及冰盖质量变化对海平面变化的贡献。预期研究成果可填补GRACE至GRACE-Follow-On期间冰盖质量变化的空白，为改进冰盖表面质量平衡模型、冰雪密实化模型等提供科学依据，并为长期监测冰盖质量变化提供可靠的新技术集成。

Ice sheet mass variation, which varies as the ongoing global climate changes, has a direct impact on sea level changes, and even threatens the safety of human lives in coastal areas. As ice sheet is located in the most frigid polar region, there are very few in situ observations available, with challenges still remaining on accurately estimating its total mass change in order to assess its current state and predict its future evolution as well as evaluate its contribution to sea level change. Therefore, we proposed to refine the density of snow/firn through combining satellite gravimetry and satellite altimetry data, with the objective of deriving continuous ice sheet mass variations within nearly 18 years based on the corrected altimetry data. .Our specific research topics mainly include: 1) developing the improved repeat-track methodology to refine ice sheet elevation change based on multiple satellite altimetry data; 2) refining the density of snow/firn though combining satellite gravimetry and satellite altimetry data; 3) deriving continuous ice sheet mass variation covering a relatively long time span, evaluating the influence from the uncertainty of snow/firn density on ice sheet mass variation and the contribution of ice sheet mass variations to sea level change..The achievements will not only fill the gap of ice sheet mass variation between GRACE and GRACE-Follow-On mission, but also provide reference for improving ice sheet surface mass balance models and firn compaction models and the integration of new technology for long-term monitoring ice sheet mass variations.