Near-coastal satellite altimetry: Sea surface height variability in the North Sea – Baltic Sea area

The radiometer wet tropospheric correction is a limiting factor of the application of near-coastal altimetry observations in the North Sea – Baltic Sea area. Using an ECMWF model based correction instead, we increase the return rate from 70% to 95%, with observations as close as 10 km from the coast. The altimetry and 39 coastal tide gauges are referenced to the same state of the art regional geoid. The two datasets are highly correlated and reveal a consistent mean dynamic topography and two distinct correlation regimes separated by the Danish islands. The combination of the two datasets in a simple statistical model is shown to estimate the sea surface height with the same error level as state of the art operational models, indicating the potential for near-coastal applications of satellite altimetry observations.