SANIFS (Southern Adriatic Northern Ionian coastal Forecasting System) is a coastal-ocean operational system based on the unstructured-grid finite-element three-dimensional hydrodynamic SHYFEM model and providing short-term forecasts. The operational chain is based on a downscaling approach starting from the large-scale system for the entire Mediterranean basin (MFS, Mediterranean Forecasting system), which provides initial and boundary condition fields to the nested system. The model is configured to provide hydrodynamics and active tracer forecasts both in open ocean and coastal waters of South-eastern Italy using a variable horizontal resolution from 3-4 km in the open sea to 500-50 m in the coastal areas. Given that the coastal fields are driven by a combination of both local/coastal and deep ocean forcings propagating along the shelf, the performance of SANIFS was verified both in forecast and simulation mode, first (i) at the large and shelf-coastal scales by comparing with a large scale survey CTD in the Gulf of Taranto and then (ii) at the coastal-harbour scale (Mar Grande of Taranto) by comparison with CTD, ADCP and tide gauge data. Sensitivity tests were performed on initialization conditions (mainly focused on spin-up procedures) and on surface boundary conditions by assessing the reliability of two alternative datasets at different horizontal resolution (12.5 and 6.5 km). The SANIFS forecasts at a lead-time of one day were compared with the MFS forecasts highlighting that SANIFS is able to retain the large scale dynamics of MFS. Those get correctly propagated to the shelf-coastal scale improving the forecast accuracy (+17% for temperature and +6% for salinity compared to MFS). Moreover the added value of SANIFS was assessed at coastal-harbour scale, which is not covered by the coarse resolution of MFS, where the SANIFS forecasted fields well reproduced the observations (temperature RMSE equal to 0.11 °C). Furthermore SANIFS simulations were compared with hourly time-series of temperature, sea level and velocity measured at the coastal-harbour scale showing a good agreement. Simulations in the Gulf of Taranto described a circulation mainly characterized by an anticyclonic gyre with the presence of cyclonic vortexes in shelf-coastal areas. A surface water inflow from open sea to Mar Grande characterizes the coastal-harbour scale.
|Titolo:||Coastal ocean forecasting with an unstructured grid model in the southern Adriatic and northern Ionian seas|
|Data di pubblicazione:||2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.5194/nhess-17-45-2017|
|Appare nelle tipologie:||1.1 Articolo in rivista|