Shipboard acoustic Doppler current profiler data from the
Southern Ocean JGOFS Process II cruise on R/V Revelle: Feb-Mar 1998 (R9802)
Principal investigators: Jack Barth & Tim Cowles, Oregon State University
Processed by: Stephen Pierce, Oregon State University
Status: final data set
Notes:
======
This data set is also available at the NODC Joint Archive for
ADCP data (http://ilikai.soest.hawaii.edu/sadcp/). The submission
to NODC contains the complete data set in binary form and full
processing details.
Data quality is excellent in general. The inherent short-term
random uncertainty for a 5-min, 16-m velocity is 2.5 cm/s at most.
This type of uncertainty will be reduced with further averaging in
depth or space. The absolute velocity may also have an unknown
systematic bias of 1 cm/s. In addition, the absolute velocity
has a random error due to navigational uncertainty of 3 cm/s
and is low-pass filtered to suppress motions with time scales of
less than 20 min (for features present throughout the 200-300 m
reference layer). This translates to at most a 7-km horizontal
spatial smoothing of the reference layer velocities.
The present submission is the commonly used simple ascii subset:
5-min average velocities in 16-m vertical bins. The columns are
as follows:
Column 1 : Yearday (1.5 == Jan. 1 at 1200 UTC)
Column 2 : Depth of the bin center (m)
Column 3 : Latitude (decimal degrees)
Column 4 : Longitude (0-360, decimal degrees)
Column 5 : East velocity (m/s)
Column 6 : North velocity (m/s)
All data records are good; there are no null values. Missing
or poor-quality data have been omitted.
Questions, contact:
===================
=====================================================================
Dr. Stephen Pierce (spierce@oce.orst.edu) http://diana.oce.orst.edu
COAS - Oregon State Univ. +----------+ o: 541-737-2425
104 Ocean Admin. Building | Burt 444 | h: 541-766-8992
Corvallis, OR 97331-5503 +----------+ f: 541-737-2064
=====================================================================
Additional processing details in the NODC format:
#DATA_DATES: 1998/2/19 14:36:38 to 1998/3/18 05:59:00
#LON_RANGE: 174.601 E to 165.91 W
#LAT_RANGE: 71.316 S to 44.791 S
#DEPTH_RANGE: 57 to 300 m
#SAC_CRUISE_ID:
#PLATFORM_NAME: R/V Revelle
#PRINCIPAL_INVESTIGATOR_NAME: J. A. Barth and T. J. Cowles
#PI_INSTITUTION: Oregon State University
#PI_COUNTRY: USA
#PROJECT: Southern Ocean JGOFS (Joint Global Ocean Flux), AESOPS
#CRUISE_NAME: R9802 or APFZ cruise RR09 (SOJGOFS Process 2)
#PORTS: Lyttelton, New Zealand --- to --- Lyttelton, New Zealand
#GEOGRAPHIC_REGION: Antarctic polar front zone, south of New Zealand along 170W
#PROCESSED_BY: Oregon State University
#NAVIGATION: GPS (Pcode and attitude)
#QUALITY_NAV:
#GENERAL_INFORMATION:
CRUISE NOTES
CHIEF SCIENTIST ON SHIP :
INSTITUTE : Oregon State University
COUNTRY : USA
SIGNIFICANT DATA GAPS : none
SPECIAL SHIP TRACK PATTERNS : long transect along 170 W, 67.7-57 S
ADCP INSTRUMENTATION
MANUFACTURER : RD Instruments (RDI)
HARDWARE MODEL : RD-VM150 Narrow band
TRANSDUCER SERIAL NUMBER : 173
FIRMWARE VERSION : 17.10
TRANSMIT FREQUENCY : 153.6 kHz
TRANSDUCER CONFIGURATION : JANUS CONCAVE
TRANSDUCER BEAM ANGLE : 30 deg.
ADCP INSTALLATION
METHOD/DESCRIPTION OF THE
ATTACHMENT TO THE HULL :
LOCATION/DEPTH ON HULL : 5 m
REPEATABLE ATTACHMENT : YES
DATE OF MOST RECENT ATTACH. : Sep-97
ACOUSTIC WINDOW : YES
ADCP INSTRUMENT CONFIGURATION
DEPTH RANGE : 57 - 300 m (bin centers)
BIN LENGTH : 16 m
NUMBER OF BINS : 28
TRANSMIT PULSE LENGTH : 16 m
BLANKING INTERVAL : 36 m
ENSEMBLE AVERAGING INTERVAL : 150 s
SOUND SPEED CALCULATION : function of temp at transducer
BOTTOM TRACKING : Yes, 20 hours at end of cruise
DIRECT COMMANDS : "FH00001" "E0004020099" "B005099" "CF63"
ADCP DATA ACQUISITION SYSTEM
SOFTWARE DEVELOPERS : RDI
SOFTWARE VERSIONS : DAS 2.48
DATA LOGGER, MAKE/MODEL : 386
ADCP/LOGGER COMMUNICATION : GPIB
USER BUFFER VERSION : UH user exit "UE4", 1920 buffer version
CLOCK : PC clock; reset if drift > 2 sec from GPS clock
SHIP HEADING
INSTRUMENT MAKE/MODEL : Sperry MK-37 Mod D/E gyrocompass
SYNCHRO OR STEPPER : synchro
SYNCHRO RATIO : 1:1
COMPENSATION APPLIED : latitude: changed daily by bridge officer
: speed: 11 knots constant
GPS ATTITUDE SYSTEM : YES: Ashtech
LOCATION OF ANTENNAS : forward
RIGID ATTACHMENT : YES
LOGGING RATE : 1 per sec
ANCILLARY MEASUREMENTS
SURFACE TEMP AND SALINITY : yes
HYDRO CAST MEASUREMENTS : yes
SEASOAR CTD MEASUREMENTS : no
RAW AGC AND SPECTRAL WIDTH : no
BIOMASS DETERMINATION : no
BEAM-AVERAGED AGC AVAILABLE?: YES
CALIBRATION NET TOWS? : Yes
ADCP DATA PROCESSING/EDITING
PERSONNEL IN CHARGE : Stephen D. Pierce
DATE OF PROCESSING : final Dec. 1999
NAVIGATION
GPS : YES
MAKE/MODEL : Trimble Tasmin P-Code
SELECTIVE AVAILABILITY : YES
P-CODE : YES
DIFFERENTIAL : NO
SAMPLE INTERVAL : 1 per sec
TIME OBTAINED RELATIVE TO
START/END OF ENSEMBLE : end
LOGGED WITH ADCP DATA : YES - user exit program
CALIBRATION
GYROCOMPASS CORRECTION : YES, profile-by-profile-rotation based
on the attitude gps HOFS (heading offsets)
BOTTOM TRACK METHOD : YES
WATER TRACK METHOD : YES
FINAL SELECTION : AMPLITUDE= 1.002 PHASE= -1.973
SOUND SPEED CORRECTIONS : YES, offset of -1.09 degrees applied
(based on underway bow thruster thermistor comparison)
: we used salinity mean from underway system: 32.33
NAVIGATION CALCULATION
NAVIGATION USED : gps
REFERENCE LAYER DEPTH RANGE : bins 10 - 15
FILTERING METHOD FOR
SMOOTHING REFERENCE LAYER
VELOCITY (FORM/WIDTH) : Blackman window function of width T= 30 min:
w(t) = 0.42 - 0.5 * cos(2 * pi *t / T) + 0.08 * cos(4 * pi * t / T).
FINALIZED SHIP VEL/POSITIONS
STORED IN DATABASE : YES
GENERAL_ASSESSMENT :
ON-STATION VS. UNDERWAY : good
VECTOR, CONTOUR, STICK PLOTS: good
COMMENTS : Data quality good in general;
relatively large blanking interval was necessary to reduce a
ringing problem. A small quantity of data at the beginning,
prior to 1998/02/19 14:36:38, actually belongs to the end of
the previous cruise and should be ignored.