Method 1: Online Calculator


T. M. van Dam, University of Luxembourg
R. Ray, Space Geodesy Branch, NASA Goddard Space Flight Center

Anyone using this data set directly or products derived from this page is requested to use the following citation:
van Dam, T. and R. Ray, 2010, Updated October 2010. S1 and S2 Atmospheric Tide Loading Effects for Geodetic Applications.

How to Use the Online Calculator:

The On-line Generator takes as input the latitude and longitude of sites where the effects of atmospheric tidal loading are to be computed. The program convolves the 4 annual mean tidal pressure fields (Cosine S1, Sine S1, Cosine S2, Sine S2) [Ray and Ponte, 2003] which are global in extent and have a spacing of 1.125 deg x 1.125 deg in latitude and longitude, with Farrell's Green's Functions in the appropriate reference frame. No ocean response to pressure is assumed.

To use the online calculator, you must chose the reference frame that you would like the results in and the output format, either amplitudes and phases or the amplitudes of the sines and cosines for the S1 and S2 tides.

The output data for each station is :

  • row 1: radial displacement (mm): dr(1), dr(2), dr(3), dr(4)
  • row 2: tangential NS displacement (mm): dn(1), dn(2), dn(3), dn(4)
  • row 3: tangential EW displacement (mm): de(1), de(2), de(3), de(4).
Then, for example, the total radial displacement at the sites for any epoch is determined using:

dr(t) = dr(1)*cos(t*ω1) + dr(2)*sin(t*ω1) + dr(3)*cos(t*ω2) + dr(4)*sin(t*ω2)

where t is in fractions of a UT1 day, and ω1=2πradians/day and ω2=4πradians/day.

Select reference frame in which displacements are requested:


Select output format:

Amplitudes of Sines and Cosines for S1 and S2
Amplitudes and phases for S1 and S2

Where are your stations located?

Paste your space, tab, comma or semicolon separated data here.

Station [4 chars a-z]Longitude [deg]Latitude [deg]