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2019-20 Honours project - Characterising upwelling of Circumpolar Deep Water at the Polar Front and investigating submesoscale processes associated with upwelling

The dataset was collected on the research voyage (IN2018_V05 on RV Investigator) and from satellite observations. The dataset includes in-situ data and satellite data collected at the Polar Front (PF) south of Tasmania in a region where the Antarctic Circumpolar Current (ACC) has a permanent meander upstream of the Macquarie Ridge. This study characterises the upwelling of Circumpolar Deep Water (CDW) in a standing meander of the ACC in the PF south of Tasmania and investigates the submesoscale processes associated with upwelling.

Simple

Identification info

Date (Creation)
2020-08-31
Date (Publication)
2020-08-31

Principal investigator

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Wang, Kai
IMAS - Hobart
Private Bag 129
Hobart
Tasmania
7001
Australia

Point of contact

CSIRO Oceans and Atmosphere - Tamsitt, Veronica
GPO Box 1538
Hobart
Tasmania
7001
Australia
ORCID ID >

Point of contact

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Phillips, Helen
IMAS - Hobart
Private Bag 129
Hobart
Tasmania
7001
Australia
ORCID ID >

Principal investigator

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Bindoff, Nathan
IMAS - Hobart
Private Bag 129
Hobart
Tasmania
7001
Australia
ORCID ID >

Credit
IMAS Honours Student Program 2019-2020
Status
Completed

Point of contact

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Wang, Kai
IMAS - Hobart
Private Bag 129
Hobart
Tasmania
7001
Australia
+61452317921

Point of contact

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - Phillips, Helen
IMAS - Hobart
Private Bag 129
Hobart
Tasmania
7001
Australia
+61 3 6226 2994
+61 3 6226 2973 (facsimile)
ORCID ID >

Temporal resolution
P0Y0M1DT0H0M0S
Topic category
  • Oceans
N
S
E
W


Temporal extent

Time period
2018-10-16 2018-11-16

Vertical element

Minimum value
0
Maximum value
300
Identifier
EPSG::5715
Name
MSL depth
Maintenance and update frequency
Not planned
Keywords (Theme)
  • BUOYANCY
  • VERTICAL VELOCITY
  • ERTEL POTENTIAL VORTICITY
  • UPPER OCEAN
NASA/GCMD Keywords, Version 8.5
  • EARTH SCIENCE | OCEANS | OCEAN PRESSURE | SEA LEVEL PRESSURE
  • EARTH SCIENCE | OCEANS | OCEAN CHEMISTRY | OXYGEN
  • EARTH SCIENCE | OCEANS | OCEAN TEMPERATURE | WATER TEMPERATURE
  • EARTH SCIENCE | OCEANS | SEA SURFACE TOPOGRAPHY | SEA SURFACE HEIGHT
  • EARTH SCIENCE | OCEANS | SALINITY/DENSITY
  • EARTH SCIENCE | OCEANS | SALINITY/DENSITY | PYCNOCLINE
  • EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | WATER MASSES
  • EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | UPWELLING/DOWNWELLING
  • EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | OCEAN MIXED LAYER
  • EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | FRONTS
Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research
  • Physical Oceanography
Keywords (Theme)
  • time
  • latitude
  • longitude
  • water pressure
  • in situ temperature
  • practical salinity
  • dissolved oxygen consetration
  • conservative temperature
  • absolute salinity
  • potential density
  • depth
  • mixed layer depth
  • dissolved oxygen saturation
  • temperature anomaly
  • salinity anomaly
  • density anomaly
  • oxygen anomaly
  • buoyancy
  • buoyancy anomaly
  • horizontal buoyancy gradient
  • distance
  • circumpolar deep water index
  • Coriolis frequency
  • buoyancy (Brunt-Vaisala) frequency squared
  • Richardson Number
  • Ertel potential vorticity
  • vertical velocity
  • Vertical shear
  • along front velocity
  • cross-front velocity

Resource constraints

Classification
Unclassified

Resource constraints

Use limitation
The data described in this record are the intellectual property of the University of Tasmania through the Institute for Marine and Antarctic Studies.

Resource constraints

Linkage
http://i.creativecommons.org/l/by/4.0/88x31.png

License Graphic

Title
Creative Commons Attribution 4.0 International License


>

Website
http://creativecommons.org/licenses/by/4.0/

License Text

Other constraints
The citation in a list of references is: citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link).
Language
English
Character encoding
UTF8
Supplemental Information
McDougall, TJ & Barker, PM 2011, 'Getting started with TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox', SCOR/IAPSO WG127, p. 28, ISBN 978-0-646-55621-5.

Content Information

Content type
Physical measurement
Description
Triaxus deployed time
Name
time

Name
time

Name
second (s)
Description
Triaxus latitude
Name
latitude

Name
lat

Name
Degrees(deg)
Description
Triaxus longitude
Name
longitude

Name
lon

Name
Degrees(deg)
Description
Triaxus, Seabird SBE911 CTD 25 sensor
Name
water pressure

Name
p

Name
Decibars (dbar)
Description
Triaxus
Name
in situ temperature

Name
T

Name
Degrees Celsius (degC)
Description
Triaxus
Name
practical salinity

Name
S

Name
Practical Salinity Unit (PSU)
Description
Triaxus
Name
dissolved oxygen consetration

Name
O

Name
Milligrams per kilogram (mg/kg)
Description
Triaxus, GSW toolbox
Name
conservative temperature

Name
CT

Name
Degrees Celsius (degC)
Description
Triaxus, GSW toolbox
Name
absolute salinity

Name
SA

Name
grams per kilogram (g/kg)
Description
Triaxus, GSW toolbox
Name
potential density

Name
sigma0

Name
kilograms per stere (kg/m3)
Description
GSW toolbox
Name
depth

Name
depth

Name
meter (m)
Description
Density increase was 0.02 kg/m3 with reference to a near-surface density value at 10 m depth.
Name
mixed layer depth

Name
mld

Name
meter (m)
Description
GSW toolbox
Name
dissolved oxygen saturation

Name
O2sat

Name
1
Description
CT
Name
temperature anomaly

Name
T_anom

Name
Degrees Celsius (degC)
Description
absolute salnity
Name
salinity anomaly

Name
S_anom

Name
grams per kilogram (g/kg)
Description
potential density
Name
density anomaly

Name
sigma0_anom

Name
kilograms per stere (kg/m3)
Description
dissolved oxygen
Name
oxygen anomaly

Name
O_anom

Name
Milligrams per kilogram (mg/kg)
Description
along-track buoyancy
Name
buoyancy

Name
b

Name
s−2
Description
along-track buoyancy
Name
buoyancy anomaly

Name
b_anom

Name
s−2
Description
along-track derivative of buoyancy
Name
horizontal buoyancy gradient

Name
b_grad

Name
s-3
Description
distance from the PF center
Name
distance

Name
dis

Name
meter (m)
Description
the profiles where have CDW
Name
circumpolar deep water index

Name
cdw_index

Name
/
Name
Coriolis frequency

Name
f

Name
/
Description
GSW toolbox, smoothed in a moving weighted average for the data in 9 dbar bins
Name
buoyancy (Brunt-Vaisala) frequency squared

Name
Nsquared

Name
s-2
Description
smoothed in a moving weighted average of 9 dbar vertically
Name
Richardson Number

Name
Ri

Name
/
Description
smoothed in a moving weighted average of 9 dbar vertically
Name
Ertel potential vorticity

Name
FPV

Name
s-3
Description
derived from SADCP and Triaxus data
Name
vertical velocity

Name
w

Name
meters per second (m/s)
Description
along the PF direction
Name
Vertical shear

Name
dus_dz

Name
m/s
Description
horizontal velocity
Name
along front velocity

Name
us

Name
m/s
Description
horizontal velocity
Name
cross-front velocity

Name
vs

Name
m/s

Distribution Information

Distribution format
  • MATLAB FILE

OnLine resource
DATA ACCESS - IN2018_V05_Triaxus [explore all files]

Resource lineage

Statement
1. Satellite data Sea surface height (SSH) gridded data were obtained from the DUACS (Data unification and Altimeter combination system) products over the Southern Ocean region [146° E, 158° E], [52.5° S, 57.5° S] during the Southern Hemisphere spring from October 16 to November 16, 2018. The satellite dataset has daily SSH data, in a 0.25° × 0.25° spatial grid, encompassing the 16° longitude × 5° latitude region. The absolute dynamic topography (adt) that is the SSH above geoid was used to identify the core of the PF meander. The adt is obtained from the calculation: adt=sla+mdt, where sla is sea level anomaly and mdt is mean dynamic topography. 2.In situ observations: voyage data a. Triaxus data The Triaxus instrument was towed behind the ship and equipped with the Seabird SBE911 CTD 25 sensor to record pressures, conductivity and temperature data. Other sensors were also installed to collect other hydrologic data like dissolved oxygen. Pressure, conductivity and temperature data were calculated using calibration factors provided by Sea-Bird and calibrations provided by CSIRO. The data were processed by automated QC to remove spikes and out-of-range values. Triaxus profiles were limited to 300 m depth with a vertical resolution of 1 dbar and an approximate 0.9-1.5 km lateral spacing between vertical Triaxus casts (averaged every 5 minutes). The oxygen data was directly measured from the dissolved oxygen sensors. The salinity was the absolute salinity. The temperature was converted to the conservative temperature at each depth. The potential density was derived from absolute salinity and conservative temperature. The Gibbs-SeaWater (GSW) Oceanographic Toolbox in MATLAB was applied for evaluating these thermodynamic properties (absolute salinity, conservative temperature, potential density and in situ density) of seawater. b. Shipboard ADCP data Shipboard Acoustic Doppler Current Profiler (SADCP) mounted on the ship hull was used to determine absolute currents in 8-m-depth bins and approximately at a 1 km lateral scale (averaged every 5 minutes) in the upper ocean in coordination with accurate heading and navigation data. Narrowband data collection was used both for the RDI Ocean Surveyor 150 kHz ADCP and the RDI Ocean Surveyor 75 kHz ADCP. The drop keel was at 6 m below the waterline during the voyage. In this study, the 150 kHz RDI ADCP measured velocities from 18 m to 500 m depth, and the data output was averaged every 5 minutes. The horizontal velocity has two components, with u being defined as the West-East (zonal) velocity component and v being defined as the North-South (meridional) velocity component. There was a spatial offset between the SADCP on the ship and the Triaxus that is towed behind the ship, which was adjusted by shifting the timestep of the SADCP back by 5 minutes. c. CTD data The voyage obtained 77 full-depth CTD casts with full hydrochemistry along 9 cross-front transects. The CTD was fitted with various sensors to collect the temperature, conductivity, pressure, dissolved oxygen and fluorescence data in a high vertical resolution. The CTD frame held 36 Niskin bottles that allowed water samples to be collected from different depths during the CTD deployments. The various parameters in the water samples, including salinity, dissolved oxygen, phosphate, silicate, nitrate plus nitrite and ammonium, were processed and analysed to calibrate the data directly on the ship.
Hierarchy level
Dataset

mdb:MD_Metadata

Metadata identifier
167f8227-af9c-4fdc-8027-56b1661c86f9

Language
English
Character encoding
UTF8

Publisher

Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) - IMAS Data Manager ()

Type of resource

Resource scope
Dataset
Metadata linkage
https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/167f8227-af9c-4fdc-8027-56b1661c86f9

Point of truth URL of this metadata record

Date info (Creation)
2020-10-19T16:55:45
Date info (Revision)
2020-10-19T16:55:45

Metadata standard

Title
ISO 19115-3:2018
 
 

Overviews

Spatial extent

N
S
E
W


Keywords

BUOYANCY Coriolis frequency ERTEL POTENTIAL VORTICITY Ertel potential vorticity Richardson Number UPPER OCEAN VERTICAL VELOCITY Vertical shear absolute salinity along front velocity buoyancy buoyancy (Brunt-Vaisala) frequency squared buoyancy anomaly circumpolar deep water index conservative temperature cross-front velocity density anomaly depth dissolved oxygen consetration dissolved oxygen saturation distance horizontal buoyancy gradient in situ temperature latitude longitude mixed layer depth oxygen anomaly potential density practical salinity salinity anomaly temperature anomaly time vertical velocity water pressure
Australian and New Zealand Standard Research Classification (ANZSRC): Fields of Research
Physical Oceanography
NASA/GCMD Keywords, Version 8.5
EARTH SCIENCE | OCEANS | OCEAN CHEMISTRY | OXYGEN EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | FRONTS EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | OCEAN MIXED LAYER EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | UPWELLING/DOWNWELLING EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | WATER MASSES EARTH SCIENCE | OCEANS | OCEAN PRESSURE | SEA LEVEL PRESSURE EARTH SCIENCE | OCEANS | OCEAN TEMPERATURE | WATER TEMPERATURE EARTH SCIENCE | OCEANS | SALINITY/DENSITY EARTH SCIENCE | OCEANS | SALINITY/DENSITY | PYCNOCLINE EARTH SCIENCE | OCEANS | SEA SURFACE TOPOGRAPHY | SEA SURFACE HEIGHT

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