Em. Dunlap et al., THE EFFECT OF ASSIMILATING ERS-1 FAST DELIVERY WAVE DATA INTO THE NORTH-ATLANTIC WAM MODEL, J GEO RES-O, 103(C4), 1998, pp. 7901-7915
The launch of the European ERS satellites has provided a new source of
wave information that is particularly suitable for use in improving w
ave forecasts in the open ocean. We have implemented and tested a simp
le system for assimilating corrections to model wave fields produced b
y the WAM model, where the corrections are derived from inverted synth
etic aperture radar (SAR) image spectra from ERS-1, Corrections are ap
plied to significant wave height, mean period and direction for wave m
odes that are detectable in both the model and the SAR data. The syste
m has been tested in a storm situation and in moderate conditions usin
g buoy data and altimeter data, as well as SAR observations for verifi
cation. Overall, it is demonstrated that the net effect of assimilatin
g SAR data is beneficial but very small. The small impact is due at le
ast partly to relatively small spatial and temporal coverage of the SA
R wave mode data. Locally larger impacts were found in the storm situa
tion in individual cases where SAR observations were collocated with i
ndependent buoy observations.