Read Me File for Nortek Vector ADV data.

0. Introductory Material

All files are named Bermud##.*, where ## is the ADV cast number (1 - 5 correspond to the sled tows.) All times reported are GMT. Data were taken until the 2 Mb data recorder filled up. Data were taken in bursts, with the burst interval (elapsed time to when the next data burst started) and number of samples (or sampling duration when divided by the sample rate). The data for a cast are all in a single column with a column for burst counter to break up the data into bursts.

The unit called count is an internal recording unit. TO convert to dB, multiply it by 0.43, however the Manufacturers will not give the reference level so these numbers can not be converted to absolute values, they are always relative to the other measurements. Correlation is the main data quality parameter. It is recommended to discard data with correlation < 70. SNR is the secondary data quality parameter but the influence of low correlation should be reflected in the correlation for data cleaning purposes.


1. Data Files
There are 4 ascii data files described below.

1.1. Bermud##.hdr
The Header file. This contains all of the instrument settings and description of the data files. The tilt and heading sensors always sample at 1 Hz. The sample rate listed is for velocity and pressure. The items that were changed from cast to cast were the sample rate (effecting internal averaging and signal processing) and the velocity range (impacting the dwell time between pulse-pairs). All other parameters should have stayed the same.

1.2. Bermud##.vhd (Header follows)
Col	Item				Unit
 1   Month                            (1-12)
 2   Day                              (1-31)
 3   Year
 4   Hour                             (0-23)
 5   Minute                           (0-59)
 6   Second                           (0-59)
 7   Burst counter
 8   No of velocity samples
 9   Noise amplitude (Beam1)          (counts)
10   Noise amplitude (Beam2)          (counts)
11   Noise amplitude (Beam3)          (counts)
12   Noise correlation (Beam1)        (%)
13   Noise correlation (Beam2)        (%)
14   Noise correlation (Beam3)        (%)

1.3. Bermud##.dat (Header follows)
Col	Item				Unit
 1   Burst counter
 2   Ensemble counter
 3   Velocity (Beam1|X|East)          (m/s)
 4   Velocity (Beam2|Y|North)         (m/s)
 5   Velocity (Beam3|Z|Up)            (m/s)
 6   Amplitude (Beam1)                (counts)
 7   Amplitude (Beam2)                (counts)
 8   Amplitude (Beam3)                (counts)
 9   SNR (Beam1)                      (dB)
10   SNR (Beam2)                      (dB)
11   SNR (Beam3)                      (dB)
12   Correlation (Beam1)              (%)
13   Correlation (Beam2)              (%)
14   Correlation (Beam3)              (%)
15   Pressure                         (m)
16   Analog input 1
17   Analog input 2
18   Checksum                         (1=failed)

1.4. Bermud##.sen (Header follows)
Col	Item				Unit
 1   Month                            (1-12)
 2   Day                              (1-31)
 3   Year
 4   Hour                             (0-23)
 5   Minute                           (0-59)
 6   Second                           (0-59)
 7   Error code
 8   Status code
 9   Battery voltage                  (V)
10   Soundspeed                       (m/s)
11   Heading                          (degrees)
12   Pitch                            (degrees)
13   Roll                             (degrees)
14   Temperature                      (degrees C)
15   Analog input
16   Checksum                         (1=failed)


2.0.