Figure S1. 10 min averaged gravity time series from the AQG-B
at PDN and corrections for perturbing effects. All time series are in
nm/s2. A: Raw gravity signal. B-G: Corrections applied
to the data, to reduce the effects of: earth tides (B), polar motion
(C), atmospheric pressure (D), ground tilt (E), drift of the RF
frequency reference (F), drift of the laser frequency (G). Correction
for the latter effect is applied during the measurement, through a
feedback loop, rather than in post-processing, as in the case of the
other perturbing parameters. The time series shown in (H) (same as the
grey curve in Figure 3A) is obtained by subtracting from the raw gravity
signal (A) the effects shown in panels B to F.