基于GRACE重力卫星研究黄土高原退耕还林以来水储量变化

研究黄土高原在退耕还林(草)工程实施以来水储量变化问题具有重要的科学和社会意义。目前的研究方法主要有两种，即传统现场采样方法和现代大地测量方法。现场采样方法效率低、成本大，无法覆盖整个区域和全深度，难于实现连续观测，因此难于研究整个黄土高原水储量变化。GRACE重力卫星是一个新的有效途径，可以连续的监测整个黄土高原的重力变化。GRACE重力卫星观测到的信号主要成分是水储量变化，还包含植被生长引起的质量变化、煤炭开采、土壤侵蚀等，而且还存在数据截断和滤波造成信号泄露与信号衰减问题。本项目拟利用GRACE及GRACE Follow on重力卫星数据，结合MODIS、土壤侵蚀、煤炭开采等数据分离水储量变化信号，然后使用合理的反演方法分离和恢复黄土高原水储量变化，计算水储量变化时间序列、趋势、空间分布及年际波动，分析解释影响水储量变化的主要因素，确定退耕还林(草)工程对黄土高原水储量的影响。

It is of great scientific and social significance to study the change of water storage in the Loess Plateau since the implementation of the Grain for Green Project. At present, there are two main research methods: the traditional field sampling method and modern geodetic survey method. With low efficiency and high cost, the field sampling method cannot cover the whole region and full depth, and it is difficult to realize continuous observation. Therefore, it is difficult to study the changes of water storage in the whole Loess Plateau. The GRACE gravity satellite is a new and effective way to continuously monitor the gravity changes of the entire Loess Plateau. The main component of gravity change observed by GRACE gravity satellite is water storage change, but also includes mass change caused by vegetation growth, coal mining, soil erosion and other signals, and there are also signal leakage and attenuation problems caused by data truncation and filtering. This project plans to use GRACE and GRACE Follow on gravity satellite data, combined with MODIS, soil erosion, coal mining and other data to separate water storage change signals. Then, a reasonable inversion method was used to separate and restore the change of water storage on the Loess Plateau, calculate the time series, trend, spatial distribution and annual fluctuation of water storage, analyze and explain the main factors affecting the change of water storage, and determine the influence of the project of Grain for Green on the water storage on the Loess Plateau.