Department of Applied Mathematics, University of Alicante, Carretera San Vicente del Raspeig s/n, San Vicente del Raspeig, E-03690, Alicante, Spain.
Helmholtz Centre Potsdam, German Research Centre for Geosciences (GFZ), Telegrafenberg, A17, D-14473, Potsdam, Germany.
Sci Rep. 2018 Sep 14;8(1):13861. doi: 10.1038/s41598-018-32082-1.
Knowledge of the Earth's changing rotation is fundamental to positioning objects in space and on the planet. Nowadays, the Earth's orientation in space is expressed by five Earth Orientation Parameters (EOP). Many applications in astronomy, geosciences, and space missions require accurate EOP predictions. Operational predictions are released daily by the Rapid Service/Prediction Centre of the International Earth Rotation and Reference Systems Service (IERS). The prediction procedures and performances differ for the three EOP classes: polar motion, rotation angle (UT1-UTC), and the two celestial pole offsets (CPO), dX and dY. The IERS Annual Report 2016 shows Rapid Service CPO predictions errors with respect to IERS 08 C04 observations in 2016 ranging from 120 to 140 μas in 40 days for dX, and 100-160 μas for dY. We test a new method for the CPO prediction based on the recent availability of sophisticated empirical models for the Free Core Nutation, a main component of the CPO variations. We found it allows predicting both CPO with error estimates for the period 2000-2016 lower than the 2016 Rapid Service products, reaching about 85 μas after 40 days and near 90 μas after a year. These results would represent a 35-40% improvement.
对地球自转变化的了解是在太空中和地球上定位物体的基础。如今，地球在太空中的方向由五个地球定向参数 (EOP) 表示。天文学、地球科学和空间任务中的许多应用都需要准确的 EOP 预测。国际地球自转和参考系统服务局 (IERS) 的快速服务/预测中心每天都会发布预测结果。三种 EOP 类别的预测程序和性能有所不同：极移、自转角度（UT1-UTC）和两个天极偏移量（CPO），dX 和 dY。2016 年国际地球自转和参考系统服务局年度报告显示，2016 年快速服务 CPO 预测误差相对于 IERS 08 C04 观测值，dX 在 40 天内的范围为 120-140 μas，dY 的范围为 100-160 μas。我们测试了一种新的 CPO 预测方法，该方法基于最近出现的复杂自由核进动经验模型，这是 CPO 变化的主要组成部分。我们发现，该方法可以预测 CPO，2000-2016 年期间的预测误差估计值低于 2016 年快速服务产品，在 40 天后达到约 85 μas，一年后达到近 90 μas。这些结果将代表 35-40%的改进。
