Here we compare atmospheric pressure loading (ATML) as computed by two
different programs using the same input pressure data and Green's functions.
The ATML was computed by Leonid Petrov and Tonie van Dam from NCEP
Reanalysis pressure data in the CM reference frame (ie solid earth plus
fluid loads) using Green's functions produced by Tonie van Dam.
The only differences between the two computations are that they use
different ocean/land masks and Leonid does not model inland seas as
Inverted Barometer but Tonie does. Also, Leonid's time series are
computed for every site whereas Tonie's are generated on a 2.5 x 2.5
degree grid and then interpolated to the geodetic sites (using
GAMIT program ATMTOASC - part of stdrel.10.2).
Time series for each site from Leonid's calculations can be found here
Time series for each site from Tonie's calculations can be found here
I computed the differences in the time series between the two (Leonid's minus
Tonie's), gridded this using GMT and plotted the differences in North, East
and Up. Click on the image below to see a moving gif for the time period
2004/01/01 to 2004/01/31.
Below I show the maximum and minimum difference over the one month period
between Leonid's and Tonie's time series - for the Up component only.
