ITSG-Grace2018 - Monthly, Daily and Static Gravity Field Solutions from GRACE

The ITSG-Grace2018 gravity field model is the latest GRACE-only gravity field model computed at Graz University of Technology, providing unconstrained monthly and regularized daily solutions as well as a long-term static field. For each month of the observation period, sets of spherical harmonic coefficients for different maximum degrees (60, 96, 120) were estimated without applying any regularization.
In order to resolve high-frequency gravity field variations as detailed as possible, a set of spherical harmonic coefficients up to degree and order 40 was co-estimated. K-band range rates with a sampling of 5 seconds and kinematic orbits with a sampling of 5 minutes were used as observations. The kinematic orbits of the GRACE satellites (Zehentner and Mayer-Gürr 2013, 2014) were processed using the GPS orbits and clock solutions provided by CODE. Additionally, a full accelerometer scale factor matrix was estimated per day (Klinger and Mayer-Gürr, 2016). The accelerometer bias was modelled through cubic splines with a node interval of six hours and estimated for each axis and day. Detailed information about ITSG-Grace2018 is available at http://ifg.tugraz.at/ITSG-Grace2018. The monthly and daily data covers the period between April 2002 and August 2016.

ITSG-Grace2018重力场模型是由格拉茨工业大学（Graz University of Technology）研制的最新纯GRACE重力场模型，可提供无约束月度解、正则化日解以及长期静态重力场解。针对观测期内的每个月份，研究团队均针对不同最大阶数（60、96、120）的球谐系数（spherical harmonic coefficients）集开展了无正则化估计。

为尽可能精细地解析高频重力场变化，本次解算还联合估计了阶数最高至40的球谐系数。观测数据采用采样间隔为5秒的K波段距离率（K-band range rates）与采样间隔为5分钟的运动学轨道（kinematic orbits）。GRACE卫星的运动学轨道解算参考了Zehentner与Mayer-Gürr（2013、2014）的方法，并基于CODE提供的GPS轨道与钟差解完成。此外，研究团队每日还需估计完整的加速度计（accelerometer）比例因子矩阵（Klinger与Mayer-Gürr，2016）；加速度计偏差采用节点间隔为6小时的三次样条函数进行建模，并针对每个轴与每日分别估计。

关于ITSG-Grace2018的详细信息可访问http://ifg.tugraz.at/ITSG-Grace2018。该数据集的月度与日数据覆盖时段为2002年4月至2016年8月。

搜集汇总

背景与挑战

背景概述

ITSG-Grace2018是由格拉茨科技大学开发的GRACE重力场模型，提供月度、日度和静态重力场解决方案，覆盖2002年4月至2016年8月。数据集包含不同最大度数（60、96、120）的球谐系数，适用于地球科学和大地测量学研究。