Geophys. Res. Lett. (2014)


Sea level has a seasonal cycle, with the amplitude and timing controlled by a number of factors, such as temperature, salinity and wind. The coastal areas of the Gulf of Mexico are at risk from changes to this cycle because there are many low lying regions.

Thomas Wahl, of the University of South Florida, and co-workers use tide gauge data from the US Gulf Coast to investigate decadal changes in seasonal sea level. The annual sea-level cycle is found to have been amplified by up to 30% since the 1990s, with eastern Gulf winter sea levels lower and summer levels higher.

In combination with atmospheric data, sea surface temperature and reconstructions, the team create regression models to explore the drivers of observed decadal variability and recent increases. Changes in atmospheric temperature, tending towards more extreme seasons, are shown to explain most of the sea level increase, which has doubled the risk of hurricane flooding for the eastern and northeastern coastlines.