Baltic Sea

water masses. This becomes obvious when examining the current speeds of moorings SE and
SW before and after the storm event where current speeds were faster after the storm than
before. It seems the storm initiated an additional oscillation in deep EGB.
The moorings deployed within the EGB give an impression on the circulation and the development
of inowing waters which leads to the question on how much of the beforehand described
eects are due to external steering or other choke points on its way from the Kattegat to the
EGB, i.e. the Stolpe Channel. To investigate the role of the Stolpe Channel in more detail,
two ADCPs were deployed at 17.5 ◦ E on either side of the channel in 75 m depth.
4.3 The Stolpe Channel
4.3.1 Hydrography of the Stolpe Channel
Prior to the deployment of the two ADCPs SFN and SFS (location see Fig. 1.1) at the outlet
of the Stolpe channel two hydrographic sections were conducted in a north-south direction at
17.5 ◦ E on 22 September and repeated seven days later on 29 September 2006. The two CTD
transects are marked in Fig. 1.1. In both transects a core of cold (2.1 ◦ C) and oxygen-rich (7.8
ml/l) water was detected in depths between 40 − 55 m. Similar conditions were also captured
some months earlier in May 2006 in the monitoring data of the Stolpe Channel's central station
BMP222 (Fig. 4.7, position see Fig. 1.1). Since water masses with low temperatures and high
oxygen levels were recorded in the hydrographic cross-sections of the EGB, it is likely that
these water masses passed the Stolpe Channel either in May 2006 and arrived in the EGB in
September of the same year. Or, another possibility is that the inow water passed the Stolpe
Channel some time between May and July, since bottom temperatures in July were cold and
salinities high, but on the other hand oxygen values were very low (1 ml/l) so this alternative
seems more unlikely.
The summerly thermocline reached to depths of 30 m both on the 22 and 29 September, see
Fig. 4.8 A and B. Similar to the EGB, lowest temperatures are found just below the thermocline
in depths between 30 m and 60 m. The temperature minimum was measured close to the
position of ADCP SFN in a depth of 50 − 55 m. Below 60 m temperatures were highest apart
from the summerly surface waters, whereas the temperature gradient in this depth coincides
with a salinity/density gradient.
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