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ROMS Modelling in Australia: current status, plans and aspirations:
John F Middleton, Moninya Roughan, Chari Pattiaratchi, Greg Ivey, Ryan Lowe, Jessica Benthuysen.and teams :
John Luick, Charles James, Mark Doubell, Helen Phillips, Helen MacDonald, Mark Baird, John Wilkin, Sarath Wijeratne, Jones, Brinkman, Wake, McConocie
• Regions and Applications
• Generic Problem
• Aspirations
• Recommendations
1) South-East ROMS - NSW, 2) Southern Australian Regional Ocean Model -SARDI, 3) High Resolution Spencer Gulf Model (hydrodynamic, waves, particles, NPZD -SARDI) 4) Kimberley (internal tides) –Ivey 5) Pilbara (internal tides) – Ivey 6) Cyclone impacts – Ivey 7) Ningaloo upwelling – Lowe8), 9) and 10) – Pattiaratchi.11) WA/SA very large scale model (dashed) -Pattiaratchi
Internal tides on NWS: Modelling of Kimberley shelf region (ROMS): Greg Ivey
Rayson, Ivey, Pattiaratchi, Jones, Brinkman (2011).Journal of Geophysical Research – Oceans, C01016, doi:10.1029/2009JC005881
Shelf modelling around the NW Cape: Nested‐modelling of Ningaloo‐Pilbara region (ROMS) ‐ Ryan Lowe
Xu, Lowe, Ivey, Pattiaratchi, Jones, Brinkman (2012).Journal of Geophysical Research – Oceans, in revision.
The Leeuwin Current:the roles of topographic trapping, mixing, and advection in a buoyancy driven eastern boundary current ‐ Jessica Benthuysen and team.
29.5oS
Alongshore geostrophiccurrent .(cm/s)
What processes contribute to the poleward current’s shelfbreak intensification?
-29 cm/s
+8 cm/s
ρ uEkman
Meridional current (cm/s)
Shelfwater
• Curvilinear-orthogonal grid,2-4 km and 30 sigma layers
• Forcing: wind, air pressure, air sea fluxes (heat and freshwater) and tides.
• Open boundaries: monthly salinity and temperature climatology,monthly mean sea levels.
Project: Ocean-shelf exchange with an emphasis on the roles of waves, tides, eddies and cross-shelf flows on carbon exchange (funded through ANNiMS)
Winter ‘snap-shot’ of temperature & Salinity
ROMS: West and southern Australia model- Chari and team
Bonny summer upwelling
Dense water formation and cascading, WA shelf
Summer Winter
ROMS
ROMS
Ningaloo and Shark Bay- Sporadic upwelling
ROMS
Satellite
ROMS
Satellite
Example features
Temp Sal Temp Sal
v- velSigma-t v- velSigma-t
Southern Australian Regional Ocean Model (SAROM) – Johns Middleton, Luick and team
Validation: against SST, historical and SAIMOS Mooring and CTD data (2005‐2011) ‐ right
Applications to date:
Studies of Spencer Gulfa) Dynamics and
Speddies (Teixeira)b) OBC for High Res
Spencer Gulf Model
SWAN Wave model – detritus re‐suspension for NPZD (James)
Larval TRANs – prawn larval dispersal (Doubell)
Fennel NPZD – carrying capacity in SG (Doubell& James).
SAROM Applications
(mmol/m
3 )
+ , non‐settled, settled
Swimming
Percentage settled after 45 days = 48 %
SEA‐ROMS (Sth East Australian ROMS) – Moninya Roughan and team
Fennel Biological Model• NO3, NH4, Phytoplankton,
Zooplankton, small and large detritus
• Initial nitrate concentrations from CARS Oct average ‐ with some adjustment to account for mixed layer depth ‐ to match that of the physical model.
• All other variables initialized with a small seeding population.
• BCs‐ Northern boundary, nudged back to initial conditions, East and South are radiative.
• Physical Model ‐ Oct 2009 simulation of the formation of an EAC Cold core eddy.
• Initial Conds SynTS + CARS
• The physical model has a 5‐day spinup. Biological model is initialised after this biological output is examined from day 7.
H. Macdonald PhD Research – unpublishedTeam: Macdonald, Roughan, Baird, Wilkin
Zoop
lankton
Phytop
lankton
Nitrate
Day 16 Day 17 Day 18 Model SST Obs SST
N P Z
H. Macdonald PhD Research ‐ unpublished
Generic Problems
• The Models: ROMS is well supported through various web sites, has lots of bolt on routines (eg SWAN NPZD). Implementation can be challenging. Australian user group would help along with annual ROMS meetings
• Meteorological Forcing:
• BOM – LAPS, ACCESS good quality but spatial and temporal gaps and no easy access via web. Can this be improved?
• NCAR/NCEP and ECMRF web sites ‐ are easily accessible and provided 4 times per day but coarse resolution. (. (1.9o X 1.9o
and 0.75º x 0.75º ).
• NOAA/NCDC provides a blended 6‐hourly 0.25 o Sea Surface Wind product.
Generic problems (cont.)
• Boundary Forcing: ROMS can be embedded in global models such as Bluelink and HYCOM ‐ care is needed to ensure exact balances of mass transports result. Errors in Bluelink/HYCOmwill result in errors in child (nested) model.
Generic problems (cont.)
• Initial Conditions: CARS provides temperature and salinity data interpolated onto a (1/4o X 1/4o) grid, at a year of weekly interval averages. The data set was last updated in 2008 and needs to be updated using the IMOS data collected since then and allowance made for ENSO and non‐ENSO years which can be important on the western and southern shelves.
Generic problems (cont.)
• CARS needs updating ‐ IMOS task?
• Alternatively SynTS can be used for model initialisation and for time‐varying boundary forcing from the surface to 2000m depth
• Skill gaps modelling : NPZD, assimilation, embedding child models inside parents – share experiencs /advances
• Skill gaps physics: correct siting of backward b.c.’s in regional models;
Aspirations – where would we like to go?
Proposed Research (unfunded as yet)
UNSW: Investigate Predictability of the EAC given Strong‐constraint 4D‐VAR Data Assimilation. Strong uptake of IMOS data streams.
SARDI/CSIRO: Great Australian Bight
SARDI/MISA: Whole of ecosystem Spencer Gulf &Gulf St Vincent
Development of local models to be informed by Australian efforts as a whole.
Recommendations?• Annual Aust. ROMS meeting (tag on to other eg AMSA/AMOS
• Use of Bluelink/HYCOM – MARVL
• Met data: Can BoM improve access to ACCESS?
• CARS needs updating to include all data
• Skill gaps (NPZD, assimilation): annual meeting will help
• Physics ,Not to forget ROMS = Regional Oceanography –Mathematical Solutions
Recommendations (cont.)
• Development of a ROMS/IMOS toolbox for model display/validation?
• eg.,MATLAB streamline
vector plot software
Coupled SWAN‐ROMS Model of Spencer Gulf
• 30‐Day Simulation of SWAN (stand‐alone) and Coupled SWAN‐ROMS.
• Wavewatch III forcing of SWAN on Southern and Western boundaries
• ACCESS Wind forcing of both SWAN and ROMS model.
• Significant Wave Height and Direction Similar
Coupled model shows increased significant wave height, especially along Eastern side and near top of Spencer Gulf.