Observation of Potential Transversal Seiching Activity in the Adriatic Sea and Connection to Bora Winds
Abstract
It is known that bays, harbours and other enclosed basins are subjected to seiches, i.e. long period oscillating fluctuations of the water surface, triggered by either the passage of cyclonic weather cells or the variation of the atmospheric conditions acting above the sea (mainly wind and air pressure) (Franco et al., 1982). The Adriatic Sea, due to its elongated and narrow shape, is commonly subjected to seiching activity. Several studies have been devoted to the analysis of seiches in the Adriatic Sea over the last decades: however, the majority of them has focused so far on longitudinal seiches, developing along the main axis of the basin (NW to SE) and mainly generated by the relaxation of mean sea level rise in the northern Adriatic due to consistent Scirocco winds. Transversal seiches (1-3 hours periodic oscillations developing along the shortest axis of the Adriatic Sea, NE to SW), on the other hand, have not been properly investigated yet. Their connection to the action of bora (northern) winds is also suggested but not readily verified. This contribution aims at filling this gap by presenting and discussing novel observations of potential transversal seiches occurring in the Adriatic Sea. Measurements of mean sea level oscillations, wind direction and intensity from stations displaced along the Italian and Croatian coastlines are elaborated and analyzed in order to inspect possible links between atmospheric forcing and mean sea level fluctuations across the Adriatic Sea. Seiche-like oscillations in the range of periods between 30 minutes and 3 hours, pertinent to transversal seiching, are consistently found at both sides of the Adriatic Sea simultaneously. A proper correlation between bora or bora-related (northern) winds and generation of seiche-like oscillations in the tidal records is not readily apparent, although it is observed that such oscillations increase whenever an intensification of wind is happening or is expected to happen in a few hours (which might be seen as a symptom of a storm cell injecting energy on the basin).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMEP068..01M
- Keywords:
-
- 3285 Wave propagation;
- MATHEMATICAL GEOPHYSICS;
- 4490 Turbulence;
- NONLINEAR GEOPHYSICS;
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL;
- 4262 Ocean observing systems;
- OCEANOGRAPHY: GENERAL