Die Kuste, 81 (2014), 273-290
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3.3 Water temperature
With respect to water temperature, there is both a ‘supercollated’ L3 satellite product for
validating the sea surface temperature (SST) and profile data in North and Baltic Sea
available.
Regarding the SST, BSH-HBM shows a very accurate reproduction of die satellite data.
Over the whole year 2008, the bias is almost in die whole NOKU-area less than 1° C
and also the RMSD between BSH-HBM and satellite data is mostly less than 1° C
(Frg. 8).
Longitude Longitude
Figure 8: Bias (left) and RMSD (right) of BSH-HBM SST compared with 'supercollated'
L3-satellite SST in 2008.
A more detailed analysis of modelled water temperature is possible at in-situ stations with
larger water depth where sensors are available at different depth levels. Near-surface and
near-bottom data have been taken into account at these stations.
The near-surface results confirm die results from the satellite based SST analysis. At
the German stations die bias is less tiian 0.5° C, die RMSD is smaller dian 0.7° C and the
correlation is above 97 %.
At larger water deptii, more pronounced deviations from observation are found. At
large deptii of more than 80 metres in the Baltic Sea die temperature is not well captured
in die simulation. Due to the very long time scales of the deep water properties in die
Baltic it is hard to say if tiiere is really a severe model deficit e.g. due to a too coarse vertical
resolution, or if most of die observed differences are due to the short one year validation-period
which make die results prone to problems in die initialization and spin-up
procedure.
Nevertheless, at German stations botii in the North Sea and in die Baltic die correlation
at bottom is mostly still more than 90 %, die RMSD is between 0.5° and 1.5° C and
the bias is between 0.2° and 2° C. All in all there is a good overall agreement between
HBM and die observed data at tiiese stations as shown exemplarily in Fig. 9.
