Verification of ACCESS-S1

These are working level pages generated by the Coupled Modeling and Climate Processes teams of the BoM Science to Services Program.

The purpose of these pages are to share verification results within the Bureau and with research partners.

These pages and their contents are NOT to be distributed without permission. If you have any comments or queries, please send an email to POAMA

Background

The ACCESS-S1 evaluation is based on the hindcast set:

• 23 years: 1990-2012
• 4 start-dates every month: 1st, 9th, 17th, 25th
• 11-member ensemble for each start
• Lead times out to 6 months

Where comparisons are made with POAMA, the evaluation is done over the common hindcast years (1990-2012), using the closest matching start dates (i.e. the 1st and 26th from POAMA) and only 11-members per start date from POAMA.

Is 23 years and 11 ensemble members enough for a robust estimation of regional skill?
For some pointers on the impact of sampling on skill calculations (and other key considerations), see here.

For details about the ACCESS-S forecast system, see:

Hudson, D., Alves, O., Hendon, H.H., Lim, E., Liu, G., Luo J.-J., MacLachlan, C., Marshall, A.G., Shi, L., Wang, G., Wedd, R., Young, G., Zhao, M., Zhou X., 2017: ACCESS-S1: The new Bureau of Meteorology multi-week to seasonal prediction system. Journal of Southern Hemisphere Earth Systems Science, 67:3 132-159 doi: 10.22499/3.6703.001.

Mean State Bias (Systematic Errors)

Climate Drivers

Australian Climate

Verification on model grid (~60km)

Verification on 5km grid (work in progress)

Teleconnections to Australian rainfall

Global Climate

Skill for Rainfall, Tmax and Tmin. Verified against ERA-Interim and CRU TS respectively.

Global Teleconnections