Shipboard acoustic Doppler current profiler data from the Southern
Ocean JGOFS Survey II cruise on R/V Revelle: Jan-Feb 1998 (R9801)
Principal investigator: 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, 10-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 10-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 4 : Latitude (decimal degrees)
Column 3 : 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: 1998/01/09 03:49:19 to 1998/02/07 18:03:37
#LON_RANGE: 173.649 E to 169.396 W
#LAT_RANGE: 67.878 S to 44.119 S
#DEPTH_RANGE: 35 to 355 m
#SAC_CRUISE_ID:
#PLATFORM_NAME: R/V Revelle
#PRINCIPAL_INVESTIGATOR_NAME: Tim Cowles
#PI_INSTITUTION: Oregon State University
#PI_COUNTRY: USA
#PROJECT: Southern Ocean JGOFS (Joint Global Ocean Flux), AESOPS
#CRUISE_NAME: R9801 or Polar Front Zone Summer Survey (SOJGOFS Survey 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 : Kenneth Coale
INSTITUTE : Moss Landing
COUNTRY : USA
SIGNIFICANT DATA GAPS : none
SPECIAL SHIP TRACK PATTERNS : long transect along 170 W, 67.8-57 S
Grid survey 1: 59.9-61.3 S, 168.9-171.9 W
Grid survey 2: 60-61.6 S, 169.4-171.9 W
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 : 25 - 489 m (bin centers)
BIN LENGTH : 16 m
NUMBER OF BINS : 28
TRANSMIT PULSE LENGTH : 16 m
BLANKING INTERVAL : 12 to 52 m
ENSEMBLE AVERAGING INTERVAL : 150 s
SOUND SPEED CALCULATION : function of temp at transducer
BOTTOM TRACKING : a little 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, Revelle underway system
HYDRO CAST MEASUREMENTS : yes
SEASOAR CTD MEASUREMENTS : yes
RAW AGC AND SPECTRAL WIDTH : yes
BIOMASS DETERMINATION : Yes, in process, by Mark Huntley & Meng Zhou
BEAM-AVERAGED AGC AVAILABLE?: YES
CALIBRATION NET TOWS? : Yes
ADCP DATA PROCESSING/EDITING
PERSONNEL IN CHARGE : Stephen D. Pierce
DATE OF PROCESSING : finalized July 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 : NO
FINAL SELECTION : AMPLITUDE= 1.014 PHASE= -2.139
SOUND SPEED CORRECTIONS : YES, underway bow thruster thermistor data
applied. Used salinity mean from underway system: 32.23
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= 20 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
We increased blanking interval to unusually large values (52 m
sometimes) to remedy a ringing problem. The ringing problem would
degrade the upper few bins significantly. Increasing the blanking
interval was effective in reducing this problem.