Free-Air Anomaly (Moving Platform)

Use the Moving Platform Gravity > Corrections by Steps > Free-Air Anomaly menu option (AGFREEAIR GX), to calculate the free-air anomaly by subtracting Total Correction (see the Application Notes below) from measured values of absolute Gravity from the L+R meter in mGal (Gabs).

Calculate Free-air Anomaly dialog options

Input absolute gravity channel

The input absolute gravity channel name. The default name is "AbsGravity".

Script Parameter AGFREEAIR.INCH

Input Eotvos correction channel

The Eotvos correction channel name.

Script Parameter AGFREEAIR.EOTVOSCORCH

Input Vacc correction channel (optional)

The Vacc (Vertical Accelaration) correction channel name.

If this field is left blank, no Vacc correction is applied.

Script Parameter AGFREEAIR.VACCCORCH

Input Tide correction channel (optional)

The tide correction channel name.

If this field is left blank, no tide correction is applied.

Script Parameter AGFREEAIR.TIDECORCH

Input Latitude correction channel

The latitude correction channel name.

Script Parameter AGFREEAIR.LATCORCH

Input Free-air correction channel

The free-air correction channel name.

Script Parameter AGFREEAIR.FACORCH

Output Free-air anomaly channel

The total corrected free-air anomaly channel name. The default name is "Free-air".

Script Parameter AGFREEAIR.OUTCH

Application Notes:

The Total Correction includes the Eötvös, Vertical Acceleration (optional), Tide (optional), Latitude, and Free-air corrections:

Total Correction = Vertical Acceleration Correction (optional) - Free Air Correction - Eötvös Correction + Latitude Correction - Tide Correction (optional)

To obtain the Free-air anomaly, the Total Correction is subtracted from measured values of absolute Gravity from the L+R meter in mGal (Gabs).

See the topics below for the correction equations: