An assessment of the quality of the ESA sea level CCI products in the coastal zone of the Northern Adriatic Sea using tide gauge measurements and coastal altimetry products

Vignudelli S., De Biasio F., Scozzari A., Zecchetto S.

Sea level  Coastal altimetry  Venice 

Since 1990's, a series of radar altimetry missions accumulated a satellite-based record of sea level that is now long enough to estimate trends. The European Space Agency (ESA) Climate Change Initiative (CCI) project on "Sea Level" has reprocessed these altimeter data over 1993-2015 to provide homogenous sea level for all altimetry missions. The ESA Sea Level CCI products are generated using open ocean altimetry data, and include along track sea level anomalies (SLA) at 1 Hz (around 7 km) and monthly gridded time series of multi-mission merged SLA at a spatial resolution of 0.25° (around 25km) from which some oceanic indicators (e.g., trends) are derived. During the CCI+ phase (2018-2019) the objective is to extend the satellite-based sea level climate record to the coastal zone with quality comparable to the open ocean. This work will report on the initial assessment of the quality of the ESA Sea Level CCI products in the coastal zone of the Adriatic Sea and in particular around the city of Venice. Tide gauges available around Venìce and Trieste will provide an accurate independent source of sea level information to be used as reference of long-term sea level variability at the coast. Coastal altimetry has demonstrated that if standard products are reprocessed with dedicated algorithms reliable data can be obtained up to few kms from the coasts. Therefore, additional along-track data sets (e.g., CTOH, COSTA, etc.) with consistent coastal processing for all missions and derived products dedicated to coastal regimes will be used to evaluate their current capabilities and perspectives for usage in long term sea level research studies.

Source: ESA 11th Coastal Altimetry Workshop, pp. 28–28, ESA - ESRIN (Frascati), 12 - 15 June 2018