This is part 9 of a series of posts in which I am searching for a large acceleration in sea level rise rate in the latter part of the 20th century. Such a rise rate acceleration is needed to reconcile the 1.8 mm per year average rise rate for the century attributed to tide gauge data and the approximately 3 mm per year rise rate for the tail end of the century attributed to the satellite data.
The Baltic Sea
There are 22 tide gauge stations in the Baltic Sea area that are at least 90% data complete from 1960 to 2005. Eighteen of those are 90% complete all the way back to 1930 and ten are 90% complete back to 1900. The weighting (using a 200 km threshold) is nearly constant for the entire 20th century (see weighting graph below). I will use the usual technique of detrending, weighting, averaging and derivatives, as shown in the following slide show. (Note that you can pause or increment the slide show forward or backward by using the buttons that appear when your cursor is placed over the image.)
The following graph makes clear that the Baltic Sea tide gauge data DOES reconcile the sea level rise rate from the tide gauge data with the higher late century rise rate from the satellite data.
See an index of the Search for Acceleration series here.
20th century rise rate average of 1.8 mm/year
Satellite data (about 3 mm/year): CU Sea Level Research Group
RLR tide gauge data: Permanent Service For Mean Sea Level