Monitor plot  - Glossary and explanations

Gravity residual:
This is an ad-hoc residual, observations minus predicted earth tide minus air pressure effect.
Ad-hoc because the time series involved here are all recorded by the gravimeter's acquisition system.
Since the plot of the latest 31 days is updated on the current day, only a reduced range of data types are available for reduction.
In particular, we don't have the Atmacs pressure effects, so we work with the local air pressure.

The currently installed prediction table is from a least-squares analysis of 2015-02-05.
Predicted earth tide:

A preliminary solution, least-squares fit of a luni-solar tide potential to the observed data, simultaneously with air pressure.

Air pressure effect:
A simple regression model, giving a coefficient in units of nm/s2/hPa (-3.286 ±0.0034)

Microseismic noise:

Generated either in the deep ocean by short-wavelength standing waves or on the continental shelves, sometimes as far aways as the Gulf of Biscay.

Big diagram shows the last one hours, sampling interval is 1 s.

Small diagram shows the latest 31 days.

MEM - Power spectrum by maximum entropy

Using the Burg algorithm, a long prediction-error filter is calculated (400 coeffcients) from the 1 smp/s residual. Eleven slices of data each 12 minutes long, shifted through one hour by 6 minutes' steps.
   The curves are colour-coded with yellowish colours for the oldest slice to blue for the most recent one. Notice the colour bar along the top of the frame. A baseline (light-blue) has been determined from a few quiet days, retrieving the mean-decibel level (i.e. the geometric mean).
   The spectra (and the baseline) are affected by the anti-aliasing filter of the gravimeter's analog-digital converter. The baseline is used in the spectrograms (follow the link "spectrograms vs. time") as their 0-dB level.

   The oceanic microseisms show up primarily in the band between 30 and 300 mHz. 
Without much careful study, alleged source region are shown by colour code, seen as vertical pajamas stripes.