On a Fortran procedure for rotating spherical-harmonic coefficients

R. H. Gooding (1) , C. A. Wagner (2)

1 Centre of Satellite Engineering Research
2 LSA - NOAA Laboratory for Satellite Altimetry

The authors describe a Fortran subroutine that rotates the coefficients of a given spherical-harmonic model (in particular the geopotential). It is based on a paper by T. Risbo, working with the -functions fundamental to axis rotations in Quantum Mechanics, his approach being equally applicable to the inclination functions of satellite geodesy (which we obtain as an option in the procedure). The subroutine applies Risbo's approach to evaluate, for a given inclination, stably and accurately, the necessary -functions up to a specified degree, whilst at the same time ‘rotating' (for each degree in turn) the values of the harmonic coefficients. We follow Risbo's helpful example by including a listing of the new subroutine.

Mots clés: Rotation Matrices; Inclination functions; Rotation of spherical harmonics; Risbo's approach

R. H. Gooding, C. A. Wagner. On a Fortran procedure for rotating spherical-harmonic coefficients. Celestial Mechanics and Dynamical Astronomy, 2010, 108 (1), pp.95-106. ⟨10.1007/s10569-010-9293-3⟩. ⟨hal-00568376⟩