Metadata from Accession 668


Experiment name:        not available
Principal Investigator: not available
PI's affiliation:       Scottish Mar Bio Assn
Mooring Name:           not available
Mooring position:       57.263 deg N,   10.362 deg W
Instrument depth:       458 meters
Seafloor depth:         2229 meters
Times:                  starts 12 Apr 1981, ends 15 Oct 1981
Time increment:         30 minutes
Instrument type:        Aanderaa


  parameter         min     mean      max       sd     days

speed (cm/sec)      0.00    19.74    66.20     9.79    185.8
dir (deg true)      0.00   164.85   359.03    84.51    185.8
u (cm/sec)        -42.67     1.51    42.57    14.65    185.8
v (cm/sec)        -60.94    -6.69    41.09    14.96    185.8
temp (deg C)        8.30     9.16     9.71     0.26    185.8
pressure (db)     551.30   572.25   886.80    33.16    185.8


BODC has provided the following cautionary note: 

The pressure measurements are only suitable for relative depth
confirmation and for evaluation of the motion of the mooring
system. The pressure record shows that the rig suffered knockdown
on occasions throughout the deployment; the most severe displace-
ment of this meter was of the order of 300m and occured during
30 to 31 May 81 and on 5 Aug 81. 

Our comments: 

There is a 7-hour episode of below threshold speed on 18 Aug 81
that may be due to a failure of the speed sensor. 

This record was made with an Aanderaa current meter. The nominal
speed threshhold of this meter is 1.5 cm/sec, and a common practice
is to set below-threshhold speeds either to the threshhold value
or to half the threshhold. In this case, however, below-threshhold
speeds were set to zero by the originating PI, as were concurrent
directions. In processing historical data we normally reset below-
threshhold Aanderaa speeds to half the threshhold, but have not
done so in this case because the direction information has been
lost. 

Move up one level.