Hobart

Seminar Abstract

Friday 24 July 2009, 11.30am (Tas time)
CSIRO Auditorium, Hobart

Karen Guihou
Visiting student (CMAR Hobart - final internship masters degree)
University of Toulon
France

High resolution altimetry products: validation in the South West Australian sector

The coastal zone is an actual important challenge. In term of ocean forecasts, shelf modelling is necessary if we want to extend the predictability of the global operational systems towards coastal and regional sub-systems. Data assimilation improves the accuracy of high resolution models and so the ocean forecasting.

1Hz (i.e ~6km) resolution altimetry data are assimilated into the Bluelink ReANalysis BRAN (http://www.bom.gov.au/bluelink/). These altimetry data are unavailable near the coastline, because of land contamination problems. Using the X-TRACK processing tool and the post-processing technique adapted specifically for coastal regions, the Centre de Topographie des Ocèans et de l'Hydrosphère (CTOH) (LEGOS, FRANCE) provides along track Sea Surface Height regional products, with a resolution of 300m (http://www.legos.obs-mip.fr/soa/altimetrie/ctoh/COTIER/).

The regional high resolution CTOH product is analysed and compared with the AVISO along track product (6km of resolution, http://www.aviso.oceanobs.com/) used in BRAN, along the South-Western Australian coast. The main oceanographic feature in this area is the Leeuwin Current (LC) an eastern boundary current flowing towards the South Pole. As the LC is a warm and narrow current with a lower density than the Indian Ocean waters, SSH map allows us to follow the LC along the Australian coastline. Moreover, the LC exhibits a high mesoscale activity, which can be tracked with altimetric products.

After smoothing, the CTOH product exhibits a usable resolution of 2 km with a better coverage near the coast (up to 10km close to the coast). Compared to AVISO, we obtain a more accurate representation of the LC on the shelf, in line with its seasonal variability. Even offshore, the high resolution product highlights mesoscale details unrevealed by AVISO. A comparison with BRAN lets us expect an improvement of the eddy resolving simulation, in case of assimilation of the high resolution CTOH product.

Seminar Recording

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Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Clothilde Langlais, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5399
Natalie Kelly, (Biology/Modelling seminars) CSIRO Marine and Atmospheric Research 0438 452 483
Jillian Enraght-Moony, (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5320
Communications Manager, Antarctic Climate and Ecosystems CRC (03) 6226 2265
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 24/07/09