Baltic Sea

Modelled volume transport through Stolpe Channel
15
10
VoltrpSF 9.5
hourly
VoltrpSF 9.5
daily
VoltrpSF 9.5
5day
VoltrpSF 12
5day
Transport (km 3 /d)
5
0
5
10
15
20/09 30/09 10/10 20/10 30/10 09/11 19/11 29/11 09/12 19/12 29/12
Date in 2006 (dd/mm)
Figure 4.26: Deep volume transports across the Stolpe Channel from model data. Hourly (blue) and
daily transport values (red) were derived from densities higher 9.5 kg/m 3 , 5-day transports (cyan) from
salinities higher 12g/kg.
from VoltrpSF 12P and VoltrpSF 12N , were already extracted from the model as 5-day means and
then sorted in positive (eastward) and negative (westward) transports. Had eastward (and also
westward) 5-day averaged VoltrpSF 9.5 transports been generated from the eastward/westward
currents presented in Fig. 4.26 as the black line, 5-day volume transports VoltrpSF 9.5P and
VoltrpSF 9.5N would have been of similar magnitude as the original 5-day VoltrpSF 12 data set
(the light blue line).
Fig. 4.26 shows westward transports of VoltrpSF 12N on one occasion only. This is reected in
the westward volume transports of VoltrpSF 12N , which are of only 16.7% and therefore 83.3%
smaller than hourly transports, compare Table 4.5.
This analysis reveals that 5-day values extracted from the model are insucient to represent
realistic magnitudes of volume transports of the Stolpe Channel and also importantly, the 5-
day mean data sets are not able to resolve uctuations frequently found in the range of 2 − 4
days. This explains why, for example, the high transport values in the Stolpe Channel on the
4 November 2006 are not visible in Fig. 4.19 nor in Fig. 4.26. The 5-day mean has its peaks
83