Decadal-to-multidecadal length-of-day oscillations revealed by an extended normal time-frequency transform and core-flow reconstructions

This dataset contains three MATLAB data files used to investigate decadal-to-multidecadal variations in Earth’s length of day and their possible deep-Earth origins. Core_Flow_Covobsx2.mat contains the COV-OBS.x2 magnetic-field-inferred core-surface flow data and the corresponding core-flow-derived ΔLOD excitation calculated from the axisymmetric toroidal flow components. Dynamical_oblateness.mat contains the Satellite-Laser-Ranging-based variation in Earth’s dynamical oblateness, ΔJ₂, used to examine the relationship between long-period rotation and gravity-field variability. LOD.mat contains the yearly ΔLOD record spanning 1700.5–2020.5, assembled from historical and modern Earth-rotation observations. Owing to the relatively low precision of the earliest observations, the principal analyses reported in the associated manuscript use the ΔLOD interval from 1750 to 2020. The time coordinates are expressed in decimal years.