Testing marine data assimilation in the northeastern Baltic using satellite SST products from the Copernicus Marine Environment Monitoring Service

摘要

Satellite SST products from the Copernicus Marine Environment Service were tested for data assimilation in thesub-regional marine forecasts. The sub-regional setup of the HBM model was used in the northeastern Baltic, covering alsothe Gulf of Finland and the Gulf of Riga. Two assimilation methods – successive corrections and optimal interpolation – wereimplemented on the daily forecasts from April to December 2015. Independent daily FerryBox data from the ship track betweenTallinn and Helsinki were used for validation. Higher SST forecast errors of the reference model were found near the shallowernorthwestern coasts. During the calm heating period in spring and early summer, the reference model produced in these regionstoo warm waters compared with the satellite and FerryBox observations. Too cold waters, compared to the observations, weremodelled during the cooling period from late summer to winter. Although data assimilation reduced these errors, improving thetreatment of coastal–offshore exchange in the core forecast model would be useful.