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AGREPS – ACCESS Global and Regional Ensemble Prediction System. Michael Naughton, David Smith, Asri Sulaiman Bureau of Meteorology CAWCR Earth System Modelling Program GIFS-TIGGE WG Meeting, June 2013 UK Met Office. ACCESS-R 12 km AGREPS-R 24 km.
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AGREPS – ACCESS Global and Regional Ensemble Prediction System Michael Naughton, David Smith, Asri Sulaiman Bureau of Meteorology CAWCR Earth System Modelling Program GIFS-TIGGE WG Meeting, June 2013 UK Met Office
ACCESS-R 12 km AGREPS-R 24 km ACCESS-G 40km (N320) – 25km (N512) AGREPS-G 80km (N144) – 60km (N216) AGREPS – ACCESS ensemble prediction system • 24-member ensemble designed for medium-range and short-range forecasting • Based on UKMO MOGREPS • Global ensemble to 10 days • Regional ensemble over Australian Region to 3 days • Global ETKF for initial condition perts • Stochastic model perturbations HI-RES 4km Currently running at 60 km & 37.5 km
AGREPS current status • APS0 AGREPS global and Australian regional systems at 80km (N144) & 37.5km L50 based on UM 6.4 ran from Jan 2011 to Mar 2013 (without model perturbations) • APS1 AGREPS global system at 60km (N216) L70 based on UM 7.6 has been from start of 2012, running daily since November 2012 (includes SKEB2 model perturbations) • APS1 AGREPS has been compared with APS0 version and overseas ensemble systems • Operational implementation of AGREPS is planned, timing still dependent on resourcing
AGREPS plans • Ensembles will be key element of data assimilation through provision of capability for flow-dependent error covariances; we plan to incorporate Met Office hybrid DA approach into future ACCESS NWP suites • Ensembles for high resolution ACCESS systems are also planned
Verification – Spread-skill T850 AGREPS N216 v N144 T850 December 2012
Verification – Spread-skill T850 AGREPS N216 EM cf ACCESS-G N320 T850 April 2013
Verification – Spread-skill c.f. other centres AGREPS N216 ECMWF NCEP JMA T850 August 2012 Southern Hemisphere