Metadata from Accession 671


Experiment name:        not available
Principal Investigator: not available
PI's affiliation:       Scottish Mar Bio Assn
Mooring Name:           not available
Mooring position:       57.277 deg N,   10.368 deg W
Instrument depth:       1068 meters
Seafloor depth:         2224 meters
Times:                  starts 16 Oct 1981, ends 28 Apr 1982
Time increment:         30 minutes
Instrument type:        Aanderaa


  parameter         min     mean      max       sd     days

speed (cm/sec)      0.00     9.30    34.60     4.84    193.8
dir (deg true)      0.00   159.22   359.05    98.59    193.8
u (cm/sec)        -19.16     1.76    24.89     6.65    193.8
v (cm/sec)        -34.59    -0.58    27.92     7.89    193.8
temp (deg C)        5.22     6.66     7.65     0.50    193.8
pressure (db)    1047.70  1062.33  1201.70    20.67    193.8


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 150m and occured during
8 to 11 March 82, on 16 March and during 22 to 27 March. 

Our comments: 

There are many below-threshhold speeds in this record. A 7-hour
below-threshhold episode on 21 Mar 82 may in fact 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. 

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