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.