An intercomparison of in situ, voluntary observing, satellite data, and modelling wind and wave climatologies

This paper presents early results from an INTAS sponsored programme, the aim of which is to evaluate global scale wave climatologies compiled from visual observations, remotely-sensed data and global wave model output. Three large scale wave climatologies are compared, namely a climatology derived from the most recent release of COADS data (1979-96), a satellite altimeter-derived climatology based on measurements from Geosat, ERS-1 and TOPEX/Poseidon (1985-97), and finally a climatology based on output from the ECMWF Reanalysis project (ERA), whose homogeneous wind fields were used to drive a global scale third generation WAM model (1979-94). The INTAS programme is investigating static differences in the climatologies (e.g. through point-by-point comparisons of co-located grid cells), and dynamic differences by comparing how the three climatologies represent interannual climate variability. Separate climatologies of wind sea (i.e. waves generated by the local wind field) and swell (waves not generated locally) are available in the COADS and ERA analyses, but not from the altimeter data.