Multi-Scale Characteristics of Sea-Level Anomalies in the Mediterranean Coast

In this study, we analyze the variations in sea level observed at Tide Gauge stations across the Mediterranean Sea, utilizing datasets spanning over 50 years. Our investigation focuses on identifying various cycles, seasonal patterns, and non-seasonal fluctuations within the data collected from the selected tide gauge stations. We employ empirical mode decomposition (EMD) and the Hilbert-Huang transform (HHT) to examine these patterns comprehensively. Additionally, we investigate the relationship between Sea Level Anomalies (SLA) and major climate phenomena such as the North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO) and El Niño–Southern Oscillation (ENSO). Our findings reveal a significant connection between the SLA and the NAO at higher frequencies (less than 3 years), while the AMO appears to be more closely associated with a longer periodicity ( more than 15 years). In addition, the considerable fluctuations observed in the HHT analysis are found to be associated with ENSO events.