Articles | Volume 12, issue 1
Ocean Sci., 12, 51–69, 2016

Special issue: Oceanographic processes on the continental shelf: observations...

Ocean Sci., 12, 51–69, 2016

Research article 15 Jan 2016

Research article | 15 Jan 2016

Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the north Adriatic Sea

W. J. McKiver1, G. Sannino2, F. Braga1, and D. Bellafiore1 W. J. McKiver et al.
  • 1ISMAR-CNR, Arsenale – Tesa 104, Castello 2737/F, 30122 Venice, Italy
  • 2ENEA Centro Ricerche Casaccia, Via Anguillarese 301, 00123 Rome, Italy

Abstract. In this work we consider a numerical study of hydrodynamics in the coastal zone using two different models, SHYFEM (shallow water hydrodynamic finite element model) and MITgcm (Massachusetts Institute of Technology general circulation model), to assess their capability to capture the main processes. We focus on the north Adriatic Sea during a strong dense water event that occurred at the beginning of 2012. This serves as an interesting test case to examine both the models strengths and weaknesses, while giving an opportunity to understand how these events affect coastal processes, like upwelling and downwelling, and how they interact with estuarine dynamics. Using the models we examine the impact of setup, surface and lateral boundary treatment, resolution and mixing schemes, as well as assessing the importance of nonhydrostatic dynamics in coastal processes. Both models are able to capture the dense water event, though each displays biases in different regions. The models show large differences in the reproduction of surface patterns, identifying the choice of suitable bulk formulas as a central point for the correct simulation of the thermohaline structure of the coastal zone. Moreover, the different approaches in treating lateral freshwater sources affect the vertical coastal stratification. The results indicate the importance of having high horizontal resolution in the coastal zone, specifically in close proximity to river inputs, in order to reproduce the effect of the complex coastal morphology on the hydrodynamics. A lower resolution offshore is acceptable for the reproduction of the dense water event, even if specific vortical structures are missed. Finally, it is found that nonhydrostatic processes are of little importance for the reproduction of dense water formation in the shelf of the north Adriatic Sea.

Short summary
First modeling work comparing SHYFEM and MITgcm performance in the north Adriatic Sea; the treatment of heat/mass fluxes at the surface affects the models skill to reproduce coastal processes; high resolution is needed close to the coast, while lower resolution in the offshore is adequate to capture the dense water event; correct river discharges and temperature are vital for the reproduction of estuarine dynamics; non-hydrostatic processes do not influence the dense water formation.