OPUS II: 
About 4 and a half years later the BSH and the Institut für Ostseeforschung Warnemünde 
(IOW, Baltic Research Institut Warnemünde) carried out a second joint experiment - OPUS II - 
from May to June, 1998. At four positions the BSH deployed bottom-mounted 300 kHz 
Workhorse ADCPs (BSH1, 2, 3, and 4, see Fig. 1). A current meter mooring with two Aanderaa 
RCM 7 current meters was deployed at station BSH5. The IOW deployed two 600 kHz bottom- 
mounted BroadBand ADCPs (RD Instruments) at positions IOW1 and 2. The ADCP at position 
BSH3 failed after about 10 hours due to leakage (see Table "Moorig Data OPUS IF’) The record 
length is 11 days for the IOW-moorings and 35 or 36 days for the BSH-moorings. All instruments 
had a sampling interval of 10 minutes. Again, the data will be used to test and validate numerical 
circulation models which are run both by the BSH and IOW. In contrast to the winter survey 
during OPUS I, the OPUS II data represent a current pattern at the beginning of the summer. 
Compared to earlier investigations of current measurements in the western Baltic by Lange, 
Mittelstaedt and Klein [1991] 1 2 , OPUS I and II represent synoptical data sets which allow the 
reconstruction of circulation patters in the Mecklenburg Bight. Therefore, for both, OPUS I and 
OPUS n, time series of the meteorological parameter wind speed, wind direction and air pressure 
are shown for the stations Puttgarden (Fehmarn), Boltenhagen, and Warnemünde. For better 
comparison with the current data, the wind direction is given in the oceanographic sense, i.e., it is 
the direction in which the wind blows. Also given is a percentage frequency distribution for wind 
speed and direction. 
FBB 1995: 
Between OPUS I and II the BSH measured the current at the Fehmambelt Buoy (FBB) 
continuously from April, 1995 until January, 1996. This site is a key position, because the 
Fehmambelt is the main passage for the inflow of dense oxygene-rich bottom water from the North 
Sea into the Baltic proper. 
Whereas from July, 13 until August, 8 the BSH maintained a current meter mooring with 
two RCM7 current meters at 8 m and 25 m depth, during the rest of the time a 300 kHz 
Narrowband ADCP or a 600 kHz BroadBand ADCPs has been used. Both instruments were 
1 Wolfgang Lange, Ekkehard Mittelstaedt, Holger Klein, 1991: 
Strömungsdaten aus der Westlichen Ostsee. Meßergebnisse aus dem Zeitraum 
1982 bis 1986 sowie historische Beobachtungen vom Feuerschiff „Fehmarn 
belt". Dt. hydrogr. Z., Reihe B, Nr.24. 
2