R D Ray, Comparisons of global analyses and station observations of the S2 barometric tide, Journal of Atmospheric and Solar-Terrestrial Physics, vol.63, pp.1085-1097, 2001.

These spherical harmonic coefficients correspond to the S2 atmospheric pressure tide as observed at the surface of the earth. The model was derived by fitting spherical harmonics to the S2 tidal constants of 427 meteorological stations. These station constants were determined from long time series (at least one year, usually much longer) of barometer measurements. The original spherical harmonic fits were taken to degree and order 10, with some slight ridge damping for regularization.

These coefficients follow the same consistent convention used in these web pages for ocean tides. Coefficients are given for prograde and retrograde waves. (In this context, "prograde" means in the direction of the tide-raising body, i.e. westward; this use follows standard tidal terminology, but it is opposite to that used for polar motion.)

Amplitude units are microbars; phase lags are in degrees.

For the important degree-2 order-2 prograde term, the standard error quoted in the above reference is 6 microbar.

S2

  n  m       D+     psi+       D-     psi-

  1  0     15.92  354.24
  1  1      8.09   87.59     26.06   16.09
  2  0     51.79  324.08
  2  1      4.08  200.38     20.79   49.41
  2  2    365.07  292.85      6.21  292.80
  3  0     36.41  341.75
  3  1      2.32  230.91      6.35  245.30
  3  2      7.80   22.93      3.54  296.31
  3  3      3.75   18.18      1.01  288.25
  4  0     16.60   91.68
  4  1      2.80  327.47      3.10  239.41
  4  2     16.43  118.97      2.33  127.63
  4  3       .40   26.49       .51  338.93
  4  4       .15   91.20       .07  227.75
  5  2      1.11  167.79      1.20  159.87
  6  2       .48   77.82       .69  253.36
  7  2       .26  120.86       .60  312.88
  8  2       .61  235.94       .16   35.63
  9  2       .05   60.81       .41  140.17
 10  2       .67   53.54       .04   56.45