Coherent patterns in long-term sea-level variability trends derived from long-term tide gauge measurements

Global long-term sea-level variability trends and regional coherence patterns were mapped based on hourly sea-level time series data from the 29 longest operating tide gauge stations distributed worldwide. We split sea-level variability into three frequency bands: (1) small-scale synoptic bands (1\textendash3 d), (2) large-scale synoptic bands (3\textendash10 d) and (3) planetary-scale bands (10\textendash100 d). We then calculated seasonal and annual trends. The most coherent result obtained involved a significant decrease in sea-level variability over the tropical and subtropical Pacific, particularly at the synoptic scale frequencies. Several other coherent regions were found and linked to changes in the global atmosphere.