Earth Oblateness (C20 and J2) from Satellite Laser Ranging, 1976 to 2025
cra:j2-oblateness-slr-1976-2025601 records5 columnsv1.0 · issued 2026-07-21
01Description
Thirty-day estimates of the degree-2 zonal gravity coefficient C20 from satellite laser ranging to up to eight satellites, with the equivalent dynamical form factor J2. J2 tracks the planet's oblateness: the redistribution of mass between high latitudes and the equator, one of the bridge observables between mass transport and rotation.
02Package Contents
| Data file (CSV) | The cleaned series, one record per row |
| README.md | Source, terms, exact cleaning steps, column definitions, limitations, citation |
| Preparation script | Reproduces the CSV mechanically from the named source file(s) |
| CHECKSUMS.txt | SHA-256 for every file in the package |
Dataset Recordcra:j2-oblateness-slr-1976-2025
Series
Earth Orientation
Coverage
1976 to 2025 (epoch 2025.79)
Resolution
30-day estimates (mid-point epochs)
Extent
601 records × 5 columns
Version
v1.0 · issued 2026-07-21
Source
CSR UT Austin, SLR 30-day C20
Package
cra_j2_oblateness_slr_1976_2025_v1.0.zip · 29 KB
Data file SHA-256
b0ed7b795b8c17cd4b664890be0f79225a315e9f7f6114f13074759da64ad966
03Drawn from this package
Measured recordOblateness variation · SLR C20 · ×1e-10 about reference
CSR, University of Texas at Austin · 30-day SLR C20 estimatesC20 variation (observed)2010–2026 linear fit1976–2000 baseline, mean ±2σLatest estimate
Drawn from this package alone. The baseline band and the linear fit are computed from the same estimates the package contains; no external series enters the figure.
04Delivery
Resolving member access.