METADATA FOR LMG SHIPBOARD ADCP #DATA_DATES: 2001/04/21 13:31:00 --- to --- 2001/06/04 18:08:00 #LAT_RANGE: 69.90 W --- to --- 52.73 W #LON_RANGE: 73.27 S --- to --- 58.71 S #DEPTH_RANGE: : 26 --- to --- 418 m #PLATFORM_NAME: R/V Laurence M. Gould #PRINCIPAL_INVESTIGATOR_NAME: Dr. Teresa K. Chereskin #PI_INSTITUTION: Scripps Institution of Oceanography #PI_COUNTRY: USA #PROJECT: Shipboard Acoustic Doppler Current Profiling on R/V LMG #CRUISE_NAME: #PORTS: Punta Arenas to Palmer Station, to Punta Arenas #GEOGRAPHIC_REGION: Southern Ocean #PROCESSED_BY: Scripps Institution of Oceanography #NAVIGATION: PCODE #QUALITY_NAV: good #GENERAL_INFORMATION: CRUISE NOTES CHIEF SCIENTIST ON SHIP : Bill Fraser, Tom Hallam, Rodger Harvey, Jose Torres, Maria Vernet, Meng Zhou, Brenda Hall INSTITUTE : COUNTRY : SIGNIFICANT DATA GAPS : SPECIAL SHIP TRACK PATTERNS : COMMENTS : ADCP INSTRUMENTATION MANUFACTURER : RDI HARDWARE MODEL : VM-150 SERIAL NUMBERS : transducer SN 536; chassis SN 631 FIRMWARE VERSION : 17.12 (but reported as 17.10) TRANSMIT FREQUENCY : 153.6 kHz TRANSDUCER CONFIGURATION : JANUS CONCAVE ACOUSTIC BEAM WIDTH : TRANSDUCER BEAM ANGLE : 30 deg. COMMENTS : ADCP INSTALLATION METHOD/DESCRIPTION OF THE ATTACHMENT TO THE HULL : The ADCP transducer is installed in the forward, starboard well, accessed from the bow thruster room. The sonar well is approx. 28x28x25 inches (lxwxh). The acoustic window installed at the bottom of the well is 17x17x2 inches and made of polyurethane. The ADCP transducer is bolted to a steel mounting plate that is secured to 4 tabs, one welded to each wall of the well. Eight bolts are used to secure the transducer to the plate, and eight bolts are used to secure the plate to the tabs (2 per tab). All 4 sonar wells on the LMG are in a pod that is protected by an "ice knife". The ice knife deflects ice and bubbles away from the pod. The orientation of the transducer is beam 3 points 45 degrees to the starboard side of forward. LOCATION/DEPTH ON HULL : nominally at 6 m REPEATABLE ATTACHMENT : The ADCP mounting fixture allows a small amount of variation in transducer orientation relative to the ship. Once the bolts are secure, the orientation does not change. The maximum variation between installations is estimated at 2 degrees. There is a procedure in place to produce a repeatable installation. When it is followed, the procedure produces an installation repeatable to better than 1 degree. DATE OF MOST RECENT ATTACH. : August 1999 (Note: LMG shipyard periods are normally during the month of August. While we do not always know whether the transducer installation changed during a shipyard period, August 1999 was the initial installation on the LMG.) ACOUSTIC WINDOW : YES COMMENTS : The transducer is mounted in a well behind a polyurethane window. The well is filled with a mixture of ethylene glycol and water. ADCP INSTRUMENT CONFIGURATION DEPTH RANGE : BIN LENGTH : NUMBER OF BINS : TRANSMIT PULSE LENGTH : BLANKING INTERVAL : ENSEMBLE AVERAGING INTERVAL : SOUND SPEED CALCULATION : FUNCTION OF TEMP AT TRANSDUCER BOTTOM TRACKING : DIRECT COMMANDS : FH00001, B009001, E0004020099, CF63 COMMENTS : COMMENTS : (output from CODAS lst_conf.cnt) Configuration History File Columns are as follows: B : CODAS logical block number BT : bottom track mode (on or off) SI : sampling interval or averaging period for ensemble (sec) NB : number of bins BL : bin length (m) PL : pulse length (m) TD : transducer depth (m) BK : blanking length (m) TR : top reference bin (m) BR : bottom reference bin (m) HO : heading offset applied by DAS (deg) HB : heading bias (deg) CRPH : compensation for roll-pitch-heading, 1:on, 0:off) yy/mm/dd hh:mm:ss B BT SI NB BL PL TD BK TR BR HO HB CRPH 2001/04/21 13:31:34 0 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/04/22 13:49:06 2 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/04/24 13:00:28 6 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/04/30 00:22:30 15 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/01 00:19:31 18 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/02 13:19:08 21 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/02 18:13:17 22 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/02 18:20:55 23 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/04 15:00:10 27 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/06 19:40:44 32 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/07 15:50:05 35 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/07 21:30:22 36 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/08 01:09:12 37 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/08 02:14:45 38 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/05/08 13:20:41 40 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/06/01 23:09:32 79 off 300 50 8 16 6 8 3 5 45.00 0.00 0001 2001/06/03 23:02:29 83 on 300 50 8 16 6 8 3 5 45.00 0.00 0001 ADCP DATA ACQUISITION SYSTEM SOFTWARE DEVELOPERS : RDI/UH SOFTWARE VERSIONS : DAS248 and UE4 DATA LOGGER, MAKE/MODEL : 200 MHz Pentium clone ADCP/LOGGER COMMUNICATION : GPIB USER BUFFER VERSION : 1920 CLOCK : PC clock, reset by UE4 if drift > 2 sec from GPS. COMMENTS : SHIP HEADING INSTRUMENT MAKE/MODEL : gyrocompass, NMEA heading supplied to the DAS pc SYNCHRO OR STEPPER : SYNCHRO RATIO : COMPENSATION APPLIED : yes GPS ATTITUDE SYSTEM : YES, Ashtech ADU2 GPS LOCATION OF ANTENNAS : main mast RIGID ATTACHMENT : YES LOGGING RATE : 1 Hz ANCILLARY MEASUREMENTS SURFACE TEMP AND SALINITY : thermosalinograph, when available PITCH/ROLL MEASUREMENTS : yes HYDRO CAST MEASUREMENTS : BIOMASS DETERMINATION : DATE OF LAST CALIBRATION : CALIBRATION COEFFICIENTS : BEAM-AVERAGED AGC AVAILABLE?: YES CALIBRATION NET TOWS? : NO COMMENTS : NAVIGATION TRANSIT : MAKE/MODEL : LOGGED WITH ADCP DATA : COMMENTS : GPS : MAKE/MODEL : SELECTIVE AVAILABILITY : P-CODE : YES DIFFERENTIAL : SAMPLE INTERVAL : 1 Hz LOCATION OF ANTENNA RELATIVE TO TRANSDUCER : TIME OBTAINED RELATIVE TO START/END OF ENSEMBLE : 2 fixes at start and end. 2 from P-code and 2 from Ashtech AVERAGING/EDITING APPLIED : LOGGED WITH ADCP DATA : YES - via UE4, UB type 1920 LOGGED INDEPENDENTLY : COMMENTS : OTHER : ADCP DATA PROCESSING/EDITING PERSONNEL IN CHARGE : Processor 1 SOUND SPEED CORRECTIONS : DATE OF PROCESSING : NOTABLE SCATTERING LAYERS : COMMENTS : CALIBRATION Used only data with Ashtech when finding a calibration correction. Applied the correction to the entire data set. GYROCOMPASS CORRECTION : Ashtech corrections to Gyro used. BOTTOM TRACK METHOD : ADCP lg0104 step size 2 Time range 110.56 to 154.75 Calculation done at 2003- 9-20 19:50 step: 2 min_depth: 25 max_depth: 1500 min_speed: 2.0 m/s max_sig: 2.5 std devs max_gap: 0.10 minutes tol_dt: 0.02 (fraction) unedited: 6312 points edited: 2965 points, 2.0 min speed, 2.5 max dev median mean std amplitude 0.9743 0.9743 0.0079 phase -0.2689 -0.2842 0.5721 WATER TRACK METHOD : ADCP lg0104 7ens Time range 113.54 to 151.69 Calculation done at 2003- 9-20 19:49 delta-u min = -100.00, max = 100.00; delta-v min = -100.00, max = 100.00 clip_amp = 0.04, clip_ph = 3.0 clip_dt = 60, clip_var = 0.050 Number of edited points: 187 out of 216 amp = 0.9767 + -0.0001 (t - 131.6) phase = -0.28 + 0.0037 (t - 131.6) median mean std amplitude 0.9750 0.9767 0.0141 phase -0.2590 -0.2816 0.8593 nav - pc 4.0000 5.1337 4.7154 var 0.0090 0.0104 0.0063 min var 0.0080 0.0088 0.0053 delta-u -0.5400 -0.3027 3.5939 delta-v -0.4300 -0.3165 3.5579 FINAL SELECTION : AMPLITUDE= 0.98 PHASE= -0.3 AGREEMENT WITH PREVIOUS CRUISES : COMMENTS : In August 2000, a sound velocity probe (SVP) was installed in the transducer well. When available, SVP data are used to correct sound speed at the transducer. A linear least squares regression of sound speed from the SVP versus transducer temperature from the ADCP is computed. ss_corrected = b + m * tr_temp b = 2.97 m = 1516.36 NAVIGATION CALCULATION NAVIGATION USED : GPS REFERENCE LAYER DEPTH RANGE : 4 to 12, PG_MIN = 50 FILTERING METHOD FOR SMOOTHING REFERENCE LAYER VELOCITY (FORM/WIDTH) : Blackman window function of width = 0.0208 days (half hour) FINALIZED SHIP VEL/POSITIONS STORED IN DATABASE : YES COMMENTS : QUALITY ASSESSMENT ON-STATION VS. UNDERWAY : VECTOR, CONTOUR, STICK PLOTS: YES, OK COMMENTS : REFERENCES (DATA REPORTS,ETC) :