New altimetry products over shelf and coastal zone from the eSurge processor.

Paolo Cipollini (National Oceanography Centre, United Kingdom)

CoAuthors

Luke West (National Oceanography Centre, United Kingdom); Helen Snaith (British Oceanographic Data Centre, United Kingdom); Phillip Harwood (CGI, United Kingdom); Craig Donlon (ESA/ESTEC, The Netherlands)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Near Real Time Products and Applications and Multi-Mission, Multi-Sensor Observations

Presentation type: Type Poster

The ESA Data User Element eSurge Project is aiming to improve the modelling and forecasting of storm surges through the increased use of advanced satellite products. The eSurge SEARS (eSurge Event Analysis and Repository Service) archive, publicly available via the eSurge Portal (http://www.storm-surge.info), contains data collected for about 200 storm surge events worldwide. Amongst these data there are coastal altimetry data from several missions: Envisat, Cryosat-2 (both SAR and PLRM), Jason-1, Jason-2 (AltiKa is being added too).
The eSurge coastal altimetry data are generated by a dedicated processor, an evolution of the processor developed in the COASTALT project, whose further development and implementation represented a significant investment by ESA within the eSurge Project. The main features of the processor are:
- retracking of the waveforms with specific models optimized for the coastal zone: R&D work carried out within eSurge lead to the development of the ALES subwaveform retracker (Passaro et al., Rem. Sens. Env., 2014) which is now the retracker of choice for pulse-limited altimetry (LRM/PLRM) in eSurge; the SAR mode waveforms of Cryosat-2 are retracked with the model developed within the ESA SAMOSA project (Ray et al., IEEE TGARS, 2014);
- corrections for ionospheric, tropospheric, pressure and wind effects, tides and sea state bias are updated with the latest available models from the reference RADS archive; these corrections are then interpolated to high-rate (20Hz) and saved with the output files, and selectively applied depending on the desired parameter of choice: for instance, tidal and pressure and wind corrections are not applied in the computation of one of the quantities of widespread use in storm surge research, the Total Water Level Envelope (TWLE) which contains tidal and high frequency atmospheric effects.
- the final products are packaged into Coastal Geophysical Data Records (CGDRs) in netCDF format, and can be downloaded by the users via ftp or OPeNDAP, or directly displayed using the visualisation tools on the eSurge portal.
In this contribution we will present examples of the products for the various missions, illustrating how they have captured the signature of surges. These include the generation of TWLE in Near Real Time from Cryosat-2 for the Xaver Storm over the North Sea in December 2013, which was carried out as part of the 'eSurge-Live' demonstration service and captured the signature of the storm over the Danish Straits.
 
Paolo Cipollini
National Oceanography Centre
United Kingdom
cipo@noc.ac.uk