Low-Frequency Sea Level Variability in the Northeastern Mediterranean

Abstract

Abstract Analyses of time series of one year of sea level data from 11 stations in the northeastern Mediterranean (Adriatic, Ionian and Aegean seas) are presented in terms of local atmospheric pressure forcing. The study focuses on low-frequency oscillations with time scales ranging from one day to several weeks, but shorter than the seasonal scale. The summer and winter seasons are analyzed separately. An empirical orthogonal function analysis of both sea level and atmospheric pressure resulted in a separation of lower frequency oscillations of planetary-wave time scale (expressed by the first mode) from the higher frequency synoptic time scale variability (included in the second mode). The first mode is related to the in-phase sea level or atmospheric pressure variations of the entire area, while the second mode represent variations for which the Adriatic Sea is out of phase with both the Ionian and Aegean seas. Only those first two modes represent a regionally coherent signal subtracting more than 90% ...