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5.2 Currents 
In the past few years, several comparisons have been made between BSHcmod and 
ADCP (Acoustic Doppler Current Profiler) measurements in the North Sea. ADCPs are 
especially suitable for such comparisons because they measure currents in the whole 
water column above the transducer. The ADCPs were placed in a bottom frame on the 
sea floor, with the transducer 0.5 m above the sea floor. The ADCP devides the water 
column into equally spaced depth cells, so called bins, which in our case had a height of 
2 metres. The ADCPs used are 300 kHz WorkHorse Sentinels manufactured by RD 
Instruments. 
A first detailed comparison was made by Klein and Dick (1999) at the light-vessel 
’’German Bight” in the summer of 1999. Besides currents, this comparison also includes 
water level and tidal current data. In general, good agreement was found between both 
two-month data sets. The main difference between model and measurement was an 
insufficient resolution of vertical gradients, which has been attributed to the model’s 
coarse vertical grid spacing. 
Another comparison was carried out from November 2 to December 12, 2000, in the 
North Sea at 53° 57’ N, 6° 30’ E north of Borkum-Riffgrund (Klein, 2001). The water 
depth was 31 m, but 27 m according to model topography. The relation between model 
layers and 2 m ADCP bins is shown in Table 4: 
Table 4: Relation between model layers and ADCP bins at Borkum-Riffgrund 
BSHcmod 
ADCP 
0 m 
bin 12: 4-6 m 
0 - 3 m no data due to side lobes! 
10 m 
bin 09: 10 m - 12 m 
20 m 
bin 04: 20 m - 22 m 
27 m 
bin 01: 26 m -28 m