南极海冰与冰盖的质量变化及其对全球海平面变化贡献的研究

The sea ice mass fluctuations and ice-sheet mass variations in Antarctica is studied using different kind of observations, such as the satellite laser altimeter data from ICESAT, the measurements from ICEBridge project, the observations from continuously operating reference stations(CORS) , gravity measurements, airborne gravity measurements, satellite gravity observations from GRACE(Gravity Recovery And Climate Experiment) and GOCE(Gravity field and steady-state Ocean Circulation Explorer), sea-floor pressure, InSAR(Synthetic Aperture Radar Interferometry), etc. .The correlation between the surface height change and the gravity variations will be studied by using satellite laser altimeter data and the gravity measurements. The model will also be studied for estimating the contribution of ice-sheet mass variations to the global change. The steric sea level change will be studied by using the temperature and salinity measurements from ARGO(the Array for Real-time Geostrophic Oceanography), and other in-situ measurements, and the global steric sea level change will be derived mainly using the ARGO measurements. The impact of the marine mass variations on the global sea level change will be studied by using the GRACE gravity models. The relationships between different sea level quantities will be studied, the total global sea level observed by satellite altimetry, the steric sea level from ARGO, and the sea level change caused by the marine mass variations. The time series of surface height change, gravity change, sea-floor pressure, sea level change, sea surface temperature, etc. will be analysis using different methods, such as EOF(Empirical Orthogonal Functions), wavelet multiscale analysis, Hilbert-Huang transformation, and multifractal analysis, to extract the main features of these time series, and to analyze the relationships. The Ensemble kalman filtering, 4D variational assimilation will be used to combine different observations for studying the global sea level, and the contributions of the sea ice mass fluctuations, ice-sheet mass variations to the global sea level will be studied.

利用卫星激光测高数据、ICEBridge数据、以及GPS连续站、重力、海底压力、InSAR等数据，研究南极冰盖高程变化与重力变化之间的相关性，研究南极冰盖的高程与质量变化，提取南极海冰厚度及其变化信息，通过研究精细的模型估算两极海冰及冰盖变化对全球海平面变化的影响；利用ARGO浮标海洋温度和盐度观测数据，结合其它海洋观测数据，分析全球比容海平面变化；利用GRACE、GOCE重力卫星地球重力场模型推算海水质量变化引起的海平面变化，分析测高海平面变化、比容海平面变化、以及质量变化引起的海平面变化等的相关性；通过主成分分析、小波多分辨分析、Hilbert-Huang变化、以及多维分形分析等方法，提取极地冰盖变化、全球海平面变化、比容海平面变化、海面温度变化等时间序列的主要特征；利用集合卡尔曼滤波、变分同化等方法，融合多源观测数据，估算极地冰盖质量变化以及海冰厚度变化等不同因素引起的海平面变化。

海平面变化是全球气候变化的一个重要指标和直接结果。由于全球气候的变暖会引起海水温度上升、陆地冰川和两极冰盖的熔化，从而会导致全球海平面上升，因此对南极海冰与冰盖的质量变化及其对全球海平面变化贡献进行研究具有显著的科学和社会效益。本项目综合利用ICESAT激光测高数据、ICEBridge数据、Cryosat-2数据、ICESAT-2激光测高数据、卫星重力等多源数据，获取了南极冰盖的高程及质量变化信息，对南极海冰的厚度及其变化进行了研究；同时基于Torus方法解算了高精度的GOCE地球重力场模型，这为利用高精度地球重力场模型来研究海平面变化提供了基础。本项目利用ARGO浮标的海洋温度和盐度观测数据，分析了全球比容海平面变化；同时利用GRACE重力卫星数据推算了由于海水质量变化引起的海平面变化，并根据卫星测高数据获取的全球海面高异常，分析了测高海平面变化与比容海平面变化之间的相关性。