利用密集GPS站数据反演陆地水储量变化及其对海平面变化的影响

陆地水储量变化与全球水循环和气候变化密切相关。与GRACE相比，GPS技术对区域质量负载敏感，然而目前基于全球稀疏GPS站（~400）的球谐函数反演只能获得大尺度的陆地水储量变化。本项目瞄准高分辨率陆地水储量变化产品的应用需求，提出利用全球密集GPS站（10000+）的坐标时间序列反演高时空分辨率的全球和区域陆地水储量变化；研究GPS站坐标非质量负载误差的削弱方法，提高坐标时间序列的精度；在此基础上，基于Fingerprint方法构建适应于全球陆地水储量反演的新方法，突破GPS站南北/陆海分布不均匀对反演空间分辨率的限制；同时为避免全球反演对测站密集区域信号的平滑，利用顾及水平方向形变的格林函数法提高中国/区域反演分辨率；进一步基于海平面方程评估陆地水储量变化对全球海平面变化的影响。研究成果可为研究气候环境变化和洪旱灾害等提供数据支撑。

Continental water storage is not only an important indicator of global water cycle and climate change, but also one of major contributors to close the sea budget. This project aims to research on the theories and methods for inverting global and regional continental water storage using dense GPS data worldwide. The key points are as followings: we first try to mitigate non-loading errors in GPS displacements, including thermo-elastic displacements, GPS draconitic errors and common mode errors; for global inversion, we propose a new Fingerprint inversion approach and modify the spherical harmonics approach of Clarke et al. 2005 to allow adjusting the low-degree loading love number simultaneously; we then apply theory of green’s function for regional inversion; we finally quantify the contributions of continental water changes to the global sea level variations, especially the long-term variations, by using sea level equation. In this contribution, we provide global and regional continental water storage changes with high-resolution, which can be regarded as a new independent data source for studying global water cycle, climate change, flood, drought, and so on.