Mediterranean Meteorological Tide Increased by Over a Millimeter

It turns out that the Mediterranean meteorological tide is increasing. Scientists have discovered that the sea level variation due to atmospheric changes has increased by over a millimeter since 1989.

"The meteorological sea level or meteorological tide component is the variation of the sea level as a result of atmospheric changes or more specifically, changes in the atmospheric pressure and the wind at the sea surface," said Alba Cid, one of the researchers, in a news release.

For the study, the researchers generated two time series for meteorological tides in the Atlantic and the Mediterranean basins in the south of Europe and the Canary Islands. In totally, they analyzed the trends from 1948 to 2009, reflected in a new Global Ocean Surges (GOS) database.

So what did they find? The results are different, depending on the period. The trends from 1948 to 1989, for example, are very small and negative in the analyzed area. This means that the meteorological tide decreased during this time period. Yet in the last two decades, from 1989 to 2009, that trend shifted.

In fact, the researchers discovered that the meteorological tides increased to a greater degree than they decreased previously. The tides present values of less than .5 mm per year in the Atlantic basin and more than 1 mm per year in several areas of the Mediterranean coast. In addition, the new database also differentiates between summer and winter in each time series; in the winter, the trends are negative while in the summer, the trends are positive.

The findings tell scientists a bit more about rising sea levels in this area. Currently, the scientists are analyzing the most extreme levels and their relation to climate patterns, such as the North Atlantic oscillation (NAO).

The findings are published in the journal Climate Dynamics.