Metadata Report for BODC Series Reference Number 1718180


Metadata Summary

Data Description

Data Category Currents -subsurface Eulerian
Instrument Type
NameCategories
Teledyne RDI 300kHz Workhorse Monitor direct-reading ADCP  current profilers
Instrument Mounting lowered unmanned submersible
Originating Country United Kingdom
Originator Dr David Smeed
Originating Organization National Oceanography Centre, Southampton
Processing Status banked
Project(s) DIMES
 

Data Identifiers

Originator's Identifier LADCP_051
BODC Series Reference 1718180
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2011-04-24 11:34
End Time (yyyy-mm-dd hh:mm) -
Nominal Cycle Interval 7.9 decibars
 

Spatial Co-ordinates

Latitude 56.14930 S ( 56° 9.0' S )
Longitude 57.62384 W ( 57° 37.4' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth 8.0 m
Maximum Sensor Depth 3496.0 m
Minimum Sensor Height -72.5 m
Maximum Sensor Height 3415.5 m
Sea Floor Depth 3423.5 m
Sensor Distribution Variable common depth - All sensors are grouped effectively at the same depth, but this depth varies significantly during the series
Sensor Depth Datum Approximate - Depth is only approximate
Sea Floor Depth Datum Approximate - Depth is only approximate
 

Parameters

BODC CODE Rank Units Short Title Title
ACYCAA01 1 Dimensionless Record_No Sequence number
ADEPZZ01 1 Metres DepBelowSurf Depth below surface of the water body
ERRVLDCP 1 Centimetres per second LADCPErrVel Current velocity error in the water body by lowered acoustic doppler current profiler (ADCP)
LCEWLW01 1 Centimetres per second CurrVelE_ADCP Eastward current velocity (Eulerian) in the water body by lowered acoustic doppler current profiler (ADCP)
LCNSLW01 1 Centimetres per second CurrVelN_ADCP Northward current velocity (Eulerian) in the water body by lowered acoustic doppler current profiler (ADCP)
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database


Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."


Narrative Documents

Instrument Description

The LADCP data were collected using the instrumentation detailed below:

Sensor Model Serial Number Calibration (UT) Comments
LADCP Teledyne RDI high-power Workhorse 300kHz 12736 - Downward looking
LADCP Teledyne RDI standard Workhorse 300kHz 1855 - Upward looking, for casts 1 to 45
LADCP Teledyne RDI standard Workhorse 300kHz 12369 - Upward looking, for casts 46 to 55

The LADCP system consisted of two ADCPs (one up-looker and one down-looker), a battery and interconnection cables mounted on on a Sea-Bird 9 11 plus CTD frame.

A high-power Workhorse ADCP from the LDEO stable was used as the downlooker throughout the entire cruise. The up-looker was one of two NOC standard Workhorses. On station 42 beam 4 became weak and on casts 43, 44 and 45 beam 4 was broken. The instrument was replaced on cast 46.

The configuration of the instruments remained unchanged during the first section in particular 25 x 8m bins, were used.

Teledyne RDI's Workhorse Monitor ADCP

The Workhorse Monitor acoustic doppler current profler (Teledyne RD Instruments) is a long-range and long-term self contained ADCP. It has a patented four beam signal (300, 600 or 1200 kHz) and a standard depth rating of 200m or 600m. It operates effectively between temperatures of -5°C and 45°C and has a velocity accuracy of ±1% ±5mm/s.

BODC Processing

LDEO processed data were provided by the originator in Matlab and ASCII formats. The LDEO processed data in ASCII format were converted into BODC internal format after discussion with the originator. All data provided were from the downward looking RDI 300 kHz Workhorse ADCP which was in operation at the time. The following table shows how the variables within the ASCII files were mapped to appropriate BODC parameter codes:

Originator's Parameter Name Units Description BODC Parameter Code Units Comments
z m Depth of LADCP bin ADEPZZ01 m -
u m s -1 Eastward velocity LCEWLW01 cm s -1 Units converted from m s -1 to cm s -1 by multiplying by 100.
v m s -1 Northward velocity LCNSLW01 cm s -1 Units converted from m s -1 to cm s -1 by multiplying by 100.
ev m s -1 Uncertainty estimates of LADCP velocity profile ERRVLDCP cm s -1 Units converted from m s -1 to cm s -1 by multiplying by 100.

All reformatted data were visualised using the in-house Edserplo software. Suspect and missing data were marked by adding an appropriate quality control flag.

Note that the more complex LDEO processed data are available on request in Matlab format.

Originator's Data Processing

Sampling Strategy

A total of 52 LADCP profiles were obtained. Profiles were collected at each of the CTD stations except for CTD station 10. LADCP profiles were not obtained on stations 2 and 16 where the CTDs were aborted.

Data processing

Preliminary shipboard processing of the LADCP data was carried out with the LDEO IX_6 LADCP processing software. Processing included preliminary 1Hz CTD data and navigation data obtained from the Seatex system. The Glonass navigation stream was used instead for cast 27 due to problems with the Seatex data.

On station VMADCP data were extracted from the preliminary processed data. These data were averaged for all samples acquired during each CTD station and a file was created showing the mean currents standard deviation and number of samples in each depth bin. VMADCP was used to verify the LADCP data and not used in the processing. Bottom tracking was included in the processing of the LADCP profiles except for 3, 4, 6, 7, 9, 11, 14, 18, 19, 20, 21, 23, 24, 25, 27, 28, 30, 34, 35, 38 and 39.

Please refer to Thurnherr (2014) and the cruise report for a more detailed processing methodology. However, please be aware that this processing guide is for software versions IX.7 to IX.10 only, and changes have been made between versions which have the potential for significantly changing the solutions.

References

Thurnherr, A. M., 2014. How To Process LADCP Data With the LDEO Software, Versions IX.7 - IX.10.


Project Information

Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean (DIMES) project document

DIMES is a US/UK field program aimed at measuring diapycnal and isopycnal mixing in the Southern Ocean, along the tilting isopycnals of the Antarctic Circumpolar Current.

The Meridional Overturning Circulation (MOC) of the ocean is a critical regulator of the Earth's climate processes. Climate models are highly sensitive to the representation of mixing processes in the southern limb of the MOC, within the Southern Ocean, although the lack of extensive in situ observations of Southern Ocean mixing processes has made evaluation of mixing somewhat difficult. Theories and models of the Southern Ocean circulation have been built on the premise of adiabatic flow in the ocean interior, with diabatic processes confined to the upper-ocean mixed layer. Interior diapycnal mixing has often been assumed to be small, but a few recent studies have suggested that diapycnal mixing might be large in some locations, particularly over rough bathymetry. Depending on its extent, this interior diapycnal mixing could significantly affect the overall energetics and property balances for the Southern Ocean and in turn for the global ocean. The goals of DIMES are to obtain measurements that will help us quantify both along-isopycnal eddy-driven mixing and cross-isopycnal interior mixing.

DIMES includes tracer release, isopycnal following RAFOS floats, microstructure measurements, shearmeter floats, EM-APEX floats, a mooring array in Drake Passage, hydrographic observations, inverse modeling, and analysis of altimetry and numerical model output.

DIMES is sponsored by the National Science Foundation (U.S.), Natural Environment Research Council (U.K) and British Antarctic Survey (U.K.)

For more information please see the official project website at DIMES


Data Activity or Cruise Information

Cruise

Cruise Name JR20110409 (JR276, UKD-2.5)
Departure Date 2011-04-09
Arrival Date 2011-04-26
Principal Scientist(s)Andrew J Watson (University of East Anglia School of Environmental Sciences)
Ship RRS James Clark Ross

Complete Cruise Metadata Report is available here


Fixed Station Information

Fixed Station Information

Station NameDrake Passage - WOCE SR1b
CategoryOffshore route/traverse

World Ocean Circulation Experiment (WOCE) Southern Repeat Section 1B - Falkland Islands to Elephant Island

WOCE Southern Repeat Section 1B is a section across Drake Passage in the South Atlantic Ocean. The nominal end points of the section (to date) are at 52° 55.74' S, 58° 00.00' W (at the south of the Falkland Islands) and 61° 03.05' S, 54° 33.10' W (off Elephant Island at the north end of the Antarctic Peninsula).

The section was first occupied by the R/V Polarstern in 1992 (Gersonde, 1993). The first UK occupation of SR1b followed on RRS Discovery later the same year. The National Oceanography Centre, Southampton (formerly known as Southampton Oceanography Centre), in collaboration with the British Antarctic Survey, have occupied the section most years since 1993 on the RRS James Clark Ross. Additionally, there were three Spanish occupations on R/V Hespérides in February 1995, 1996 and 1998 (Garcia et al., 2002). A Drake Passage summary report for RRS James Clark Ross cruises between 1993 - 2000 has been produced.

A table of cruises which occupied SR1b is presented below with links to the relevant cruise reports (were available).

Cruise Country Start Date End Date
R/V Polarstern ANT 10-5 Germany 08-08-1992 26-09-1992
RRS Discovery D198 United Kingdom 11-11-1992 17-12-1992
RRS James Clark Ross JR0a United Kingdom 20-11-1993 18-12-1993
RRS James Clark Ross JR0b United Kingdom 13-11-1994 30-11-1994
R/V Hespérides 29HE19951203 Spain 03-12-1995 06-01-1996
R/V Hespérides 29HE19960117 Spain 17-01-1996 05-02-1996
RRS James Clark Ross JR16 United Kingdom 13-11-1996 07-12-1996
RRS James Clark Ross JR27 United Kingdom 17-12-1997 08-01-1998
R/V Hespérides 29HE19980730 Spain 27-07-1998 27-08-1998
RRS James Clark Ross JR47 United Kingdom 13-01-2000 17-02-2000
RRS James Clark Ross JR55 United Kingdom 21-11-2000 14-12-2000
RRS James Clark Ross JR67 United Kingdom 19-11-2001 17-12-2001
RRS James Clark Ross JR81 United Kingdom 18-12-2002 02-01-2003
RRS James Clark Ross JR94 United Kingdom 28-11-2003 16-12-2003
RRS James Clark Ross JR115 United Kingdom 01-12-2004 19-12-2004
RRS James Clark Ross JR139 United Kingdom 05-12-2005 12-12-2005
RRS James Clark Ross JR163 United Kingdom 06-12-2006 15-12-2006
RRS James Clark Ross JR193 United Kingdom 29-11-2007 08-12-2007
RRS James Clark Ross JR194 United Kingdom 12-12-2008 20-12-2008
RRS James Cook JC031 United Kingdom 03-02-2009 03-03-2009
RRS James Clark Ross JR195 United Kingdom 19-11-2009 26-11-2009
RRS James Clark Ross JR242 United Kingdom 06-12-2010 18-12-2000
RRS James Clark Ross JR276 United Kingdom 09-04-2011 26-04-2011
RRS James Clark Ross JR265 and JR254D United Kingdom 27-11-2011 24-12-2011
RRS James Cook JC069 United Kingdom 31-01-2012 21-03-2012
RRS James Clark Ross JR281 United Kingdom 17-03-2013 27-04-2013
RRS James Clark Ross JR299 United Kingdom 08-03-2014 29-03-2014
RRS James Clark Ross JR306 United Kingdom 10-01-2015 20-01-2015
RRS James Clark Ross JR15003 United Kingdom 17-12-2015 13-01-2016
RRS James Clark Ross JR16002 United Kingdom 10-11-2016 03-12-2016

References

García, M. A., I. Bladé, A. Cruzado, Z. Velásquez, H. García, J. Puigdefàbregas and J. Sospedra, 2002: Observed variability of water properties and transports on the World Ocean Circulation Experiment SR1b section across the Antarctic Circumpolar Current. J. Geophys. Res. 107 (C10) 3162, 10.1029/2000JC000277.

Gersonde, R., 1993: The Expedition Antarktis X/5 of RV Polarstern in 1992. Berichte zur Polarforschung, 131, 167 pp.

Other Series linked to this Fixed Station for this cruise - 1089197 1089204 1089216 1089228 1089241 1089253 1089265 1089277 1089289 1089308 1089321 1089333 1089345 1089357 1089369 1716401 1716413 1716425 1716437 1716449 1716450 1716462 1716474 1716486 1716498 1716505 1716517 1716529 1718075 1718087 1718099 1718106 1718118 1718131 1718143 1718155 1718167 1718179 1718192 1718211 1718223 1718235

Other Cruises linked to this Fixed Station (with the number of series) - JC031 (105) JC069 (UKD-3) (18) JR16002 (61) JR19931120 (JR00a) (30) JR19941113 (JR0B) (29) JR19961128 (JR16) (29) JR19971217 (JR27) (54) JR20000113 (JR47) (29) JR20001121 (JR55) (31) JR20021224 (JR81) (32) JR20031211 (JR94) (30) JR20041201 (JR111, JR115) (35) JR20071129 (JR171, JR193, JR196 Leg1, JR212) (32) JR20081212 (JR194, JR197) (30) JR20091118 (JR195, JR198) (33) JR20101205 (JR242) (9) JR20111127 (JR254D, JR264, JR265) (31) JR20130317 (JR252B, JR272B, JR273A, JR281, UKD-4) (64) JR20140309 (JR293 Leg1, JR299 Leg1, UKD-5) (21) JR20150110 (JR305, JR306) (31)


BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain