EVALUATION OF OCEAN WINDS AND WAVES FROM VOLUNTARY OBSERVING SHIP DATA

This paper considers the problem of the accuracy of Voluntary Observing Ship (VOS) wind and wave data, using individual wind and wave reports from the COADS (Comprehensive Ocean-Atmosphere Data Set). Additional information on the accuracy of marine wind and wave observations was available from a pilot questionnaire, SHIPMET, which was distributed among 400 marine officers with the aim of discovering the actual practice of marine meteorological observations onboard merchant vessels. The evaluation of true wind is one of the most impor-tant sources of error in wind observations. Estimates of the possible effects of inaccurate evaluation of true wind are presented. An estimation of random obser-vational errors in wave parameters shows that wave fields can be successfully evaluated from the VOS data. Some approaches are recommended to remove systematic biases in visual wave estimates. Despite considerable progress in the development of satellite instruments and modelling, Voluntary Observing Ship (VOS) data are still the main source of our knowledge about ocean winds and waves, especially for the decades before th