A high-resolution, 1-year suite of 4D-Var OSSEs exploring the impact of XBT observations on state estimates of the East Australian Current

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Abstract
This data is output from the Regional Ocean Modeling System (ROMS) simulations that comprise a suite of four 4D-Var Observing System Simulation Experiments (OSSEs) of the East Australian Current (EAC). The model has a horizontal resolution of 2.5-6 km in the cross shelf direction and 5 km in the along shelf direction, and 30 vertical s-levels. The model domain covers the southeastern Australia oceanic region from 25.1-41.5°S and 147.1-162.2°E, and the grid is orientated 20 degrees clockwise to be predominantly orientated alongshore. These experiments test the impact on the state estimate and representation of the EAC in the presence of subsurface temperature (XBT) observations. Each experiment has varying observation repeat frequencies: quarterly, monthly, fortnightly and weekly. This dataset contains the temperature variable (and associated coordinates and dimensions) for the period Jan 2012 to Jan 2013. All variables in the netcdf are described with metadata. Some data has been removed to reduce file size but full datasets can be obtained by contacting the authors. The ROMS configuration files (header and in files) and the forcing files are linked in the associated dataset (https://doi.org/10.26190/unsworks/24146).
Persistent link to this record
http://hdl.handle.net/1959.4/100733
DOI
https://doi.org/10.26190/unsworks/24440
Link to External Data Repository
Electronic Location
Contact Information
Please contact Colette Kerry (c.kerry@unsw.edu.au) or Moninya Roughan (mroughan@unsw.edu.au).
Research Data Creator(s)
Corporate/Industry Contributor(s)
Publication Year
2022-11-01
Resource Type
Dataset
Keyword(s)
East Australian Current
Regional Ocean Modelling System (ROMS)
Data Assimilation
Oceanography
UNSW Faculty
Files
download README.txt 2.01 KB R Markdown File
download output_2W_temp_8005_8401.nc 1.61 GB The Network Common Data Form
download output_M_temp_8005_8401.nc 1.61 GB The Network Common Data Form
download output_Q_temp_8005_8401.nc 1.61 GB The Network Common Data Form
download output_W_temp_8005_8401.nc 1.61 GB The Network Common Data Form
Related dataset(s)
A high-resolution, 1-year, suite of 4D-Var Observing System Simulation Experiments of the East Australian Current System using the Regional Ocean Modeling System
Dataset
This data is output from the Regional Ocean Modeling System (ROMS) simulations that comprise a suite of four 4D-Var Observing System Simulation Experiments (OSSEs) and one free-running simulation of the East Australian Current (EAC). The model has a horizontal resolution of 2.5-6 km in the cross shelf direction and 5 km in the along shelf direction, and 30 vertical s-levels. The model domain covers the southeastern Australia oceanic region from 25.1-41.5°S and 147.1-162.2°E, and the grid is orientated 20 degrees clockwise to be predominantly orientated alongshore. This zipped dataset contains model output, model forcing and configuration files and source code. The ROMS output is in the form of netcdf files. Each output file is a single data assimilation cycle (5-days), with daily averaged values. Each file contains the standard list of numerical output, including: zeta, ubar, vbar, ubar_eastward, vbar_northward, u, v, w, temp, salt, shflux, ssflux, sustr, svstr, as well as grid information. All variables in the netcdf are described with metadata. Also included are the ROMS configuration files (header and in files) required for setting up the simulations using the open-source, publically available ROMS v3.9 source code. A zip-file of the ROMS source code is included which when combined with the forcing and configuration files, can re-run the experiments. Forcing files are included for the Ref state experiment and OSSEs. Some data has been removed to reduce file size but full datasets can be obtained by contacting the authors.
A high-resolution, 22-year, free-running, hydrodynamic simulation of the East Australia Current System using the Regional Ocean Modeling System
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The data is from a Regional Ocean Modeling System free-running, hydrodynamic simulation of the East Australian Current System. The model has a horizontal resolution of 2.5-6 km in the cross-shore direction and 5 km in the alongshore direction, and 30 vertical s-levels. The model domain covers the southeastern Australia oceanic region from 25.1-41.5S and 147.1-162.2E, and the grid is orientated 20 degrees clockwise to be predominantly orientated alongshore. The time period covered is 1 Jan 1994 to 30 Sept 2016. The model output provided are daily averages of the following variables: Two-dimensional variables: Sea surface height (zeta), barotropic cross-grid velocity (u) and barotropic along-grid velocity (v) Three-dimensional variables: Temperature (temp), salinity (salt), cross-grid velocity (u), along-grid velocity (v) and vertical velocity (w)
A high-resolution, 22-year, free-running, hydrodynamic simulation of the East Australia Current System using the Regional Ocean Modeling System (Version 2.0).
Dataset
The data is from a Regional Ocean Modeling System free-running, hydrodynamic simulation of the East Australian Current System. The model has a horizontal resolution of 2.5-6 km in the cross-shore direction and 5 km in the alongshore direction, and 30 vertical s-levels. The model domain covers the southeastern Australia oceanic region from 25.1-41.5 S and 147.1-162.2 E, and the grid is orientated 20 degrees clockwise to be predominantly orientated alongshore. The time period covered is 1 Jan 1994 to 30 Sept 2016. The model outputs provided are daily averages of the following variables: Two-dimensional variables: Sea surface height (zeta), barotropic cross-grid velocity (u) and barotropic along-grid velocity (v)Three-dimensional variables: Temperature (temp), salinity (salt), density (rho), cross-grid velocity (u), along-grid velocity (v) and vertical velocity (w), temperature time rate of change (temp_rate), temperature horizontal advection term (temp_hadv), temperature vertical advection term (temp_vadv), temperature horizontal diffusion term (temp_hdiff), temperature vertical diffusion term (temp_vdiff). In this version, the heat budget terms (temp_rate, temp_hadv, temp_vadv, temp_hdiff and temp_vdiff) are set to be zeros on the land.
A high-resolution reanalysis of the East Australian Current System assimilating an unprecedented observational data set using 4D-Var data assimilation over a two-year period (2012-2013). Version 2017.
Dataset
For the EAC region, we combine a high-resolution state-of-the-art numerical ocean model with a variety of traditional and newly available observations using an advanced variational data assimilation scheme. The numerical model is configured using the Regional Ocean Modelling System (ROMS 3.4) and takes boundary forcing from the BlueLink ReANalysis (BRAN3). For the data assimilation, we use an Incremental Strong- Constraint 4-Dimensional Variational (IS4D-Var) scheme, which uses the model dynamics to perturb the initial conditions, atmospheric forcing, and boundary conditions, such that the modelled ocean state better fits and is in balance with the observations. In addition to the traditional data streams (satellite derived SSH and SST, Argo profiling floats and XBT lines) we exploit newly available observations collected by Australia's Integrated Marine Observing System (IMOS). These include velocity and hydrographic observations from a deep-water mooring array (the EAC transport array, 27.5S) and several moorings on the continental shelf (27.5S, 30S and 34S), surface radial velocities from a high-frequency (HF) radar array (at Coffs Harbour, 30S), and temperature and salinity observations from ocean gliders.
Related publication(s)
Gwyther, D. E., Kerry, C., Roughan, M., and Keating, S. R.: Observing system simulation experiments reveal that subsurface temperature observations improve estimates of circulation and heat content in a dynamic western boundary current, Geosci. Model Dev., 15, 6541–6565, doi.org/10.5194/gmd-15-6541-2022, 2022
Gwyther, D. E., Keating, S. R., Kerry, C., and Roughan, M.: How does 4DVar data assimilation affect the vertical representation of mesoscale eddies? A case study with OSSEs using ROMS v3.9, Geosci. Model Dev. Discuss. [preprint], doi.org/10.5194/gmd-2022-204, in review, 2022
Kerry, C., Powell, B., Roughan, M., and Oke, P.: Development and evaluation of a high-resolution reanalysis of the East Australian Current region using the Regional Ocean Modelling System (ROMS 3.4) and Incremental Strong-Constraint 4-Dimensional Variational (IS4D-Var) data assimilation, Geosci. Model Dev., 9, 3779–3801, 2016. doi.org/10.5194/gmd-9-3779-2016
Kerry, C. G., Roughan, M., & Powell, B. S. (2018). Observation impact in a regional reanalysis of the East Australian Current system. Journal of Geophysical Research: Oceans, 123, 7511– 7528. doi.org/10.1029/2017JC013685
Li, Junde, Moninya Roughan, and Colette Kerry. "Variability and Drivers of Ocean Temperature Extremes in a Warming Western Boundary Current", Journal of Climate 35, 3 (2022): 1097-1111, 2022. doi.org/10.1175/JCLI-D-21-0622.1
Related grant(s)
an end-to-end ocean weather information system for the blue economy - METEOROLOGICAL SERVICE OF NEW ZEALAND LIMITED (METSERVICE) - ARC LINKAGE PROJECT INDUSTRY PARTNER CONTRIBUTION - LP170100498
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