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- EAC cumulative
transport
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Legend
○ Argo
◆ Glider
⇉ Radar
> Drifter
○ Ship
● Moorings
▬ EAC cumulative
transport
transport
EAC Array
Daily estimates of East Australian Current (EAC) properties calculated from the CSIRO EAC gridded mooring product.
The upper left plot is the time-series of the EAC transport summed from North Stradbroke to the outer EAC mooring and from the sea surface to 1500 m depth (solid black line). The green dot identifies the day being displayed on the page.
The map below is our 6-day Sea Surface Temperature (SST) composite product, with the daily cumulative EAC transport from North Stradbroke to the outer EAC mooring overlain (solid black line). The transport value at the mid-point and end of the distance between North Stradbroke to the outer EAC mooring is provided (numbers written near the larger black dots). Black dots show locations of moorings, with larger black dots indicating the mid-point and end of the array.
The plots on the right show the EAC mooring array temperature, salinity, and northward and eastward velocity interpolated onto a 1-2 km grid along the mooring line segment (black dashed line on SST map). The first column are the daily property sections, and the second column are the anomalies from the 2012-2022 seasonal climatology. The small black dots show the available data at each mooring which are used to create the filled mooring data and EAC gridded data product. The black dots at the surface indicate the SST and sea surface salinity that are included in the gridded product.
Method (CSIRO EAC gridded mooring product): (1) A 5-day filter is applied to the hourly-depth mooring data to remove tides and other high frequency processes. (2) Data are interpolated to a common daily time stamp to create the daily-depth temperature and salinity data. (3) An Iterative Completion Self-Organizing Maps (ITCOMPSOM) method, based on the SOM (Self Organising Maps) neural network machine learning algorithm, is used to fill temporal and vertical data gaps. (4) The filled velocity, temperature and salinity are interpolated onto a 1-2 km regular grid between the North Stradbroke Island and outer EAC mooring.
EAC Array
○ Argo:
pink circle at the location of any profile made in the window t0 +/- 12hrs; click on the circle to see the Argo profiles of temperature and salinity.
◆ Glider:
small diamonds (pink and black) indicate 6-hourly glider locations,
pink when the glider is in the 24hr window around t0; click on the diamonds to see the glider profiles.
⇉ Radar:
the average velocity using all available hourly radar velocities from the IMOS radar facility
within a specified time window around t0.
Eg (3-12h avg) indicates a minimum of 3 hourly radar velocity estimates are required within a 12 hour window.
Blue (red) vectors are plotted over waters warmer (cooler) than the mean value in the colorbar axis.
> Drifter:
6 hourly Global Drifter Program surface drifter (drogued at 15m on deployment) within a window of -2 to +1 day around t0.
Location and velocity are indicated with pink arrow heads.
○ Ship:
Underway water temperature, plotted hourly, from ships with hull-mounted intake. These include the RV Investigator (MNF), RV Solander and RV Cape Ferguson (AIMS), and the Spirit of Tasmania 2, Sea Flyte and Stadacona from (IMOS Ships of Opportunity Facility).
Data within t0 +/- 1day is indicated with a small black dot at the ship location and a black
circle indicates the measurement occurred within 12 hours of t0.
● Moorings:
location of moorings included in the EAC array, with larger dots indicating the mid-point and end of the array. The cumulative transport values shown on the map (in Sv) are calculated from the westernmost mooring up to these two points. We show both values to show the cumulative transport associated with the core of the EAC (i.e., often located on the western half of the array).
▬ EAC cumulative transport:
daily cumulative EAC transport from North Stradbroke to the outer EAC mooring, summed from the sea surface to 1500 m depth.
Selected isobaths: grey and cyan contours, in metres.
Adjusted Sea Level (ASL=ASLA plus Mean Dynamic Topography)): white contours every 0.1 m.
Geostrophic velocity: black arrows, where length indicates both speed and distance something would travel over a 12hr or 24hr period (as indicated) at this velocity. Derived from ASL.
The latest ASL (NRT00) map is usually dated 4 days behind real time, as indicated.