Evidence of Near-Surface Density Stratification as a Factor in Extreme Seiche Events at Ciutadella Harbor, Menorca Island

Large-amplitude harbor seiches at Ciutadella on Menorca Island in the western Mediterranean are related to local atmospheric conditions and it has been suggested that the seiche forcing mechanism involves the transfer of atmospheric energy to baroclinic modes in offshore waters. To explore this concept we examined the relationship between seasonal patterns of harbor seiche activity and water temperature. Results indicate that during the season of harbor water cooling, the probability of large harbor seiche activity varies linearly with water temperature. During the season of water warming, however, the probability of large seiche activity varies exponentially with the rate of water warming which is maximum at the summer solstice. These patterns in large seiche activity are in accord with published accounts and may result from seasonal changes in near-surface density stratification of the water offshore of Ciutadella.