Sensitivity of free and forced oscillations of the Adriatic Sea to sea level rise

Abstract

ABSTRACT: The expected global warming will cause a sea level rise (SLR) that, in addition to directeffects on coastal areas, will affect ocean dynamics. In the Adriatic Sea, seiches, tides and stormsurges will change in a way that will depend on the possible human interventions to counteractfloods. Such actions have 2 extremes: a full compensation strategy (FCST), preserving the presentcoastline by dams, and a no compensation strategy (NCST) that allows a free expansion of the seainto the low plains. Numerical models were used to describe the different scenarios. FCST wouldresult in increased wave speed and reduced friction, while NCST would give a larger basin exten-sion. In the former case, the resonant period was shortened and moved away from the period of tides:the amplitude of these, and also the surge height, would be reduced (if all other conditions are main-tained), while seiches would show an overall larger range. In contrast, the absence of counter-measures would lengthen the resonant period, giving larger tidal range in the northern part andstronger surges. In the case of NCST, assuming an extreme 10 m SLR, dramatic effects would beobserved on the semidiurnal tide and the second seiche that would almost double their range at thecoast. The results emphasize the strong difference stemming from alternate compensation strategies,but they also show that the changes in the amplitude of the sea surface oscillations are small withrespect to the SLR; indeed, not relevant for the variations of level expected for the next 100 yr.KEY WORDS: Global warming · Sea level rise · Adriatic Sea · Defense strategy