Represent Ferry box
sea surface temperatures
the SST in the Baltic Sea?
21. September 2010
passenger ferry “Finnmaid” and the merchant vessel “Transpaper”,
equipped with a ‘Ferry Box’, ply
the Baltic Sea virtually non stop. Water temperatures are automatically
taken at a water depth of about 3-4 meters every
20 seconds, and together with air temperatures sent by satellite once an
hour, and immediately available in the internet at: The
Baltic Sea Portal (BSP). Do they represent the statistical mean SST
date as shown in shown the SST
map (BSP), for the 20. Sept.2010, 17:00
There are days which show extraordinary SST variations.
The two days, 20th and 21st
September 2010 may serve as an example. The
next left figure are the data from the “Finnmaid” that had been
immediately net-published between the 19. Sept (Helsinki Travemünde in
green) to 21. Sept. (Travemünde – Helsinki in red); here
in PDF. The figure to the right shows only the journey from
Travemünde to Helsinki (20/21 Sept.) and the salinity, which the BSP
presented as “Temperature
and salinity in the Baltic Sea 20 - 21 September 2010” . The route was east of Gotland.
During the first part of the round trip (green line), as
well as on the way back to Helsinki ( red
line) the SST drop for several hours by almost 10° C.
her out-bound trip the “Finnmaid” passed Gotland in the west of
Gotland, as did the “Transpaper” on the same day, in
“Transpaper” sailed from Gothenburg (Lübeck) to Kami (17.09. brown),
and back (18.-21.Sept. red), passing Gotland only in the west of the
island. Although both vessels sailed the same route west of Gotland, and
in a narrow time period (19. Sept), the SST data are very different.
That is surprising , and may raise questions whether the data can be
immediately be used for research.