Assimilation and statistical modelling of altimetry in a coastal storm surge forecast system

Kristine S. Madsen (DMI, Denmark)

CoAuthors

Jacob L. Høyer (DMI, Denmark); Weiwei Fu (University of California, USA); Lars Jonasson (DMI, Denmark)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Science Results from Satellite Altimetry: Finer scale ocean processes (mesoscale and coastal)

Presentation type: Type Poster

It is challenging to capture storm surges with satellite altimetry, since the time scale is on the order of hours, the spatial scale a few hundred kilometres, and the largest impact is in coastal regions. The combination of satellite and tide gauge observations in a statistical model has been shown to be useful for assessing storm surges in the North Sea and Baltic Sea. However, the standard along-track altimetry products have limited quality in coastal areas and are not available within approximately 20 km of the coast.
A revised statistical model has been developed and made operational in the ESA eSurge project to provide 2-D fields of near-real time sea surface height. The statistical model has been derived using coastal altimetry products from eSurge and Pistach to provide a high quality blended product for the North Sea and Baltic Sea. The new product using coastal altimetry products will be presented and validated and the benefits of using coastal altimetry data will be assessed.
Within eSurge, the statistical model has been assimilated into a hydrodynamic model for a set of storm surge events, to assess the impact of using coastal altimetry observations for storm surge predictions. Validation against independent tide gauges show improvements in the model performance after assimilation and suggest new ideas for future experiments.
Figure: Sea level [m] on January 8, 2005 at 21:00 UTC as modelled by the HBM ocean model after assimilation of the DMI statistical sea level model.
 
Assimilation and statistical modelling of altimetry in a coastal storm surge forecast system
Kristine S. Madsen
DMI
Denmark
kma@dmi.dk