Transcript Seasonal Prediction System and Applications at the Australian Bureau of Meteorology Guomin Wang

Seasonal Prediction System and
Applications at the Australian
Bureau of Meteorology
Guomin Wang
With contributions from Harry Hendon, Oscar Alves,
Claire Spillman, Faina Tseitkin and Xiaobing Zhou
Centre for Australian Weather and Climate Research:
A partnership between the Bureau of Meteorology and CSIRO
Outline
POAMA (Predictive Ocean Atmosphere
Model for Australia) & a brief update
on ACESS
Great Barrier Reef SST Prediction
Leeuwin Current Prediction
POAMA Overview
•The Bureau Dynamical Seasonal Prediction
System POAMA
•First version went operational in 2002
•A new version (POAMA1.5) became
operational recently and a newer version is
in development
•POAMA development evolves as part of
Australian Earth System Modelling project
ACCESS
•Webpage POAMA.BOM.GOV.AU
POAMA Model Components
Atmospheric Model
BAM T47L17 -> T63L17 -> ACCESS(UKMO+LSM)
3h
  f (U10  usurface )
SST , usurface
OASIS Coupler
time
Heat flux, P-E
Ocean Model
ACOM2 lat/lon/lev=0.5~1.5/2/25 -> AusCOM
Hindcasts Design
• Control run initialized at 00Z on the first day of
each month, 1980-2006
• Extra 9 members initialized prior to control run
initial time in progressively 6 hours interval
• Each hindcast is integrated for 9 months
Skill Assessment: ACC for SST and Heat Content
SST
+1
+3
+5
H300
Skill Assessment: ACC for SST Pacific & Indian Ocean Indices
Nino3.4
IOD
ACC
RMS
ACCESS: The Australian Community Climate and Earth System Simulator
Atmosphere
CABLE
Coupler
AusCOM
Ocean
(MOM4p1 code)
Coupled Modelling Team
Land Surface/Carbon Cycle Team
Model Systems Team
Atmospheric Modelling Team
AusCOM
Sea ice
(CICE4 code)
Kamal Puri
ACESS Component Model Testing: UM
UM
OBS
BAM
ACESS Component Model Testing: AusCOM
AusCOM
Zonal annual mean velocity (1990-2001) along the equator (X Zhou)
GODAS
Claire Spillman
The Great Barrier Reef
 Largest coral reef system
in the world
 Habitat for richly diverse
community of species
 Sporadic bleaching in
GBR since 1982
 Mass bleaching events in
1998 & 2002
Claire Spillman
Coral bleaching & what we can do
 Loss of symbiotic algae (zooxantheallae) from coral tissues



during times of stress
High SST is primary cause of bleaching
Mortality increases with frequency, duration & magnitude of
high temperatures
Bleaching in the GBR tends to occur Feb-April
 Satellite based now-casts e.g. NOAA
Coral Reef Watch Program
 Advance warning assists

management
Improve recovery times by
reducing stress on affected
areas e.g. limited access
Image courtesy of GBRMPA
Claire Spillman
GBR SST Index
 Mean SST anomalies in
0.81
0.81
GBR region
 Model captures general
variability
0.63
0.63
0.55
0.55
0.46
Spatial correlation of GBR Index
Spillman & Alves, 2008
0.46
Claire Spillman
GBR SST Index Skill
 Predictability: Maximum skill limit (perfect
model assumption)
SST anomaly correlations
Spillman & Alves, 2008
Claire Spillman
Coral Bleaching HotSpots
http://coralreefwatch.noaa.gov
 Anomalies
obs
Feb 2002 Lead=0
model

calculated using
maximum monthly
climatology 19822006
Coral bleaching
events often noted in
areas where
HotSpots > 1oC
Claire Spillman
Degree Heating Weeks
http://coralreefwatch.noaa.gov
obs
obs
model
 Indicates accumulation of
thermal stress that coral
reefs have experienced over
past 12 weeks
 DHW = Sum (Weekly
Hotspots) over last 12
weeks
 Depict the duration and
strength of thermal stress
that results in bleaching.
 Severe coral bleaching
likely where DHW > 10
Claire Spillman
Model
Bleaching
Products
obs
obs
 Weekly
model

obs
model

products
Combine
with GBR
Index?
How best to
assess skill?
Example GBR Forecasts
 Daily forecasts
produced in real
time
 Used by GBRMPA
with ReefTemp
http://poama.bom.gov.au
http://www.cmar.csiro.au/remotesensing/
gbrmpa/ReefTemp.htm
Claire Spillman
Seasonal Prediction of the Leeuwin Current: Observed Features
Freemantle sea level
(FSL) is indicative of
volume transport
variation of the
Leeuwin Current (M.
Feng).
Use FSL as a proxy
for Leeuwin Current
strength.
Annual Mean of SST & top 300m Currents from Reanalyses
Annual Mean of V-Current along 32ºS from Reanalyses
Pattern Correlation of V anomalies along 32ºS from Reanalyses
82
83 84 85 86 87 88
89 90
91 92 93 94
95
Years
B ` a
i
ffffffffffffC
` a
PCORR va t , va t
i  1,2,3,4
96 97 98
99 00
01
02 03 04
05 06
Fremantle Sea Level and Ocean Heat Content
Observation vs Forecast Skill
Obs relationship between H300 and SLA at Freo
HCNW = 15-25ºS,112-120ºE
H300 ACC Skill at leadtime=7
Fremantle Sea Level and SST
Observation vs Forecast Skill
N34 = 5ºS-5ºN; 170º-120ºW
Downscaling POAMA Forecasts to Fremantle SLA
Skill of Fremantle SLA Prediction from Downscaling Scheme
Nino4
NWHC
Both Combined
Persist
FSLA Forecasts 1982-2006
FSLA Obs
FSLA Lead 3
FSLA Lead 6
FSLA Lead 9
82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06
Years
Summary
•
Introduction of the Australian Bureau’s Dynamical
Seasonal Prediction System POAMA and ACCESS
•
Exploring potential for regional SST forecast products
(Great Barrier Reef) with dynamical system
•
Challenge for regional ocean current simulation and
prediction. A downscaling scheme with dynamical
model inputs shows useful skill for the Leeuwin
Current.