Dynamic response of the Black Sea elevation to intraseasonal fluctuations of the Mediterranean sea level

摘要

Response of the Black Sea elevation to intraseasonal sea level changes in the Mediterranean is studied using satellite altimetry data and a linear analytical model. Satellite observations show that the nonseasonal sea level in the Black Sea ((1)) is coherent with that in the Aegean and Marmara Seas ((0)) but lags behind them by 10-40days at subannual periods. The observed time lag is mainly due to friction that constrains the exchange through the Bosphorus Strait. Using realistic friction and characteristic (0) forcing in the model, we find that the amplitude of (1) reaches the amplitude of (0) at about 1year period, and the time lag increases from 10 to 22days at periods 50-250days. Freshwater fluxes, atmospheric pressure, and to a smaller extent the along-strait wind also influence the Black Sea elevation, but sea level fluctuations in the Mediterranean appear to be the dominant forcing mechanism.