An hourly, two way coupling of the atmospheric and ocean-wave model was introduced. Predicted ocean waves now provide information to the atmospheric boundary layer.
Other modifications introduced at the same time were:
the use of both significant and standard wind level winds, temperatures and humidities from radiosondes (geopotential is no longer used);
the use of extra off-time data, mostly SYNOPs and DRIBUs;
the use of 1D-Var SSM/I total column water vapour;
extension of the use of GOES high-resolution winds to the northern extratropics;
the use of more TOVS channels over land;
the observation operator for 10m winds is now unified for scatterometer, DRIBU and SYNOP observations.
Implemented: 29 June 1998
Resources
ECMWF Newsletter: "Progress with wind-wave interaction" from Newsletter No.80 and "Recent improvements to the ECMWF 4D-Var data assimilation" from Newsletter No.81