The Earth's mass redistribution due to deglaciation and recent ice sheet melting causes changes in the Earth's gravity field and vertical land motion in Greenland. The changes are because of ongoing mass redistribution and related elastic (on a short time scale) and viscoelastic (on time scales of a few thousands of years) responses. These signatures can be used to determine the mantle viscosity. In this study, we infer the mantle viscosity associated with the glacial isostatic adjustment (GIA) and long-wavelength geoid beneath the Greenland lithosphere. The viscosity is determined based on a spatio-spectral analysis of the Earth's gravity field and the land uplift rate in order to find the GIA-related gravity field. We used different land uplift data, that is, the vertical land motions obtained by the Greenland Global Positioning System (GPS) Network (GNET), gravity recovery and climate experiment (GRACE) and glacial isostatic adjustment (GIA) data, and also combined them using the Kalman filtering technique. Using different land uplift rates, one can obtain different GIA-related gravity fields. As shown in this study, the mantle viscosities of 1.9 × 10²² Pa s and 7.8 × 10²¹ Pa s for a depth of 200–700 km are obtained using ICE-6G (VM5a) model and the combined land uplift model, respectively, and the GIA-related gravity potential signal.

中文翻译：

---

来自大地水准面和格陵兰不同土地隆起数据的地幔粘度

由于冰川消融和最近的冰盖融化导致的地球质量重新分布导致地球重力场和格陵兰岛垂直陆地运动的变化。这些变化是由于持续的质量再分配和相关的弹性（在短时间尺度上）和粘弹性（在几千年的时间尺度上）响应。这些特征可用于确定地幔粘度。在这项研究中，我们推断了与格陵兰岩石圈下方的冰川均衡调整（GIA）和长波大地水准面相关的地幔粘度。粘度是基于对地球重力场和陆地隆起率的空间光谱分析来确定的，以便找到与 GIA 相关的重力场。我们使用了不同的土地隆起数据，即 格陵兰全球定位系统（GPS）网络（GNET）获得的垂直陆地运动、重力恢复和气候实验（GRACE）和冰川均衡调整（GIA）数据，并使用卡尔曼滤波技术将它们组合起来。使用不同的土地隆起率，可以获得不同的 GIA 相关重力场。如本研究所示，地幔粘度为 1.9 × 10²²  Pa s 和 7.8 × 10 ²¹  Pa s 深度为 200-700 km 分别使用 ICE-6G (VM5a) 模型和联合陆上隆起模型以及 GIA 相关的重力势信号获得。