engleski

Response of the Adriatic sea-level slope to the air-pressure gradient and wind forcing at subsynoptic frequencies

Six to eight years of sea level, air pressure and wind data, collected at three locations along the east Adriatic coast, are used to examine variability at low frequencies (ť0.01-0.1 cpd). Seasonal energy spectra show that for all the time series energy at time scales between 2 and 100 days is greater in winter than in summer. There is substantial wind energy in subsynoptic frequency range, the greater part of which is in the longshore component. In order to explain the inverse barometer (IB) overshoot, recorded throughout the Mediterranean, response of sea level to the air pressure and wind forcing at low frequencies was examined through multiple linear regression and cross-spectral analysis. The inclusion of wind stress from three coastal stations, or of the first principal component mode of wind stress, reduces but does not fully account for the IB overshoot. A simple model of a linear system with two inputs, one of which is measured with error, and one output, is developed. It is shown that the parameter estimates of such a model are biased by measurement error of the input.

sea level; planetary-scale atmospheric forcing; isostatic adjustment

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