In my ongoing quest to find a better way to align sea level records from tide gauges at different locations, I’ve tried a new strategy.
Different tide gauges are at different levels, so we need to offset them by a constant to align them before we combine them. But they don’t just show different base levels, they also have different vertical land movement (VLM). To put different tide gauge stations on a “global” scale we need to cancel that out, which means we need to remove a trend from the data — because the primary effect of vertical land movement is rise or fall at a constant rate which differs from place to place, sometimes dramatically.



