CoAuthors

Ole Andersen (DTU Space, Elektrovej bldg 328, 2800 Kongens Lyngby, Denmark); Lars Stenseng (DTU Space, Elektrovej bldg 328, 2800 Kongens Lyngby, Denmark); Per Knudsen (DTU Space, Elektrovej bldg 328, 2800 Kongens Lyngby, Denmark)

Sentinel-3 offers independent SAR altimetry along new groundtracks and can hence provide independent evaluation of existing mean sea surfaces. We perform an evaluation of the recent available mean sea surfaces using one year of 1 Hz Sentinel-3A data taking into account the shift in temporal average and coverage. Seninel-3A will cover 2016/2017 with a temporal average around January 2017, whereas e.g., the DTU15MSS is an average of altimetry from 1993-2012 with an averaging median year in 2003. Hence, recent models for sea level changes must be introduced in order to account for 14 years of sea level changes which can regionally contribute with a signal on the decimeter scale. The low SAR instrumental noise allows for a relatively smooth mean profile computation with only one year of data.

Subsequently a more detailed coastal evaluation of the Mean sea surface models in the North Sea and Danish waters are performed by using the 20 Hz Sentinel 3 data to study the impact of SAR altimetry on short wavelength Mean sea surface determination. Due to the difference between LRM and SAR wavelength shorter than 100 km important for coastal signal mapping is better determined using SAR altimetry than with conventional altimetry which is the base for most current mean sea surfaces.
The evaluation of the possible residual SLA signal along Sentinel tracks can be used for updating the DTU15 MSS and be introduced into the DTU18MSS based on 25 years altimetry to be released in 2018.