The Centre for Australian Weather and Climate ResearchA partnership between CSIRO and the Bureau of Meteorology

AGREPS – ACCESS Global and Regional Ensemble Prediction System

Michael Naughton, David Smith, Asri SulaimanBureau of MeteorologyCAWCR Earth System Modelling Program

GIFS-TIGGE WG Meeting, June 2013UK Met Office

AGREPS – ACCESS ensemble prediction system

Currently running at 60 km & 37.5 km

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

ACCESS-G 40km (N320) – 25km (N512) AGREPS-G 80km (N144) – 60km (N216)

ACCESS-R 12 km AGREPS-R 24 km

HI-RES 4km

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 N144T850 December 2012

Verification – Spread-skill T850

AGREPS N216 EM cfACCESS-G N320

T850 April 2013

Verification – Spread-skill c.f. other centres

AGREPS N216ECMWFNCEPJMA

T850August 2012Southern Hemisphere