Baltic Sea

to the right (perpendicular) to the wind, which also leads to a sea level rise on the right hand
side of the channel (in wind direction) and a fall on the left hand side. At the same time
downwelling occurs on the right hand side, which is compensated by upwelling on the left
hand side. Coastal jets are established in wind direction on both sides of the channel to be
compensated by a return ow in the central and deep areas of the basin. Comparable current
situations could be observed in the Stolpe Channel. The eastward deep current core measured
by SFN was detected in depths between 65 - 71 m, (Fig. 4.27 B), while at ADCP SFS it were
recorded between 52 - 68 m (Fig. 4.27 C). The eastward currents at SFN lagged 38 by one
day, whereas at SFS they responded immediately and went simultaneously with the regional
wind 38. But on both sides of the channel eastward currents always lasted for 2 - 4 days,
acting pulse-like. Every time the regional wind turned westward, expressed as a negative peak
in Fig. 4.27 A, the along-slope components of SFN (Fig. 4.27 B) recorded enhanced eastward
bottom currents. On the 25 September, 11 - 15 October, 29 October, 1 - 3 November and
10 November 2006 westward winds were observed and subsequently strong eastward currents
were recorded between 27 September and 3 October, 12 - 18 October, 2 - 3 November and
6 - 8 November 2006, Fig. 4.27 B. Associated amplitudes were somewhat stronger in the north
than in the south, whereas their overall velocity was of the same magnitude. However, the
eastward deep current occupied a thicker deep layer in the south than in the north. The rapid
changes in the regional wind from 27 to 31 October, alternating from east to west to east were
not reected by the deep currents of SFN. Instead SFN showed two strong cores of westward
currents on 29 and on 31 October 2006. Only the for 3 days lasting strong westward wind
at the beginning of November was responded to immediately by strong eastward currents
through the whole water column. From around 10 November until the end of the current
series solely eastward winds were measured, steadily increasing from 19 November until 15
December 2006. During this time two events of eastward bottom currents were recorded,
the rst between 18 - 20 November and the second between 26 November and 1 December
2006. The rest of the recording time was mainly characterised by westward currents. Even
though the general trend was a continuous increase of 38, regular drops in the wind speed
occurred. These weakened winds coincided with eastward currents, for example around the 19
and 29 November and 11 December 2006. This could lead to the assumption that prolonged
weak eastward winds prioritise density driven boundary currents.
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