Upload
frederica-houston
View
222
Download
1
Tags:
Embed Size (px)
Citation preview
Predictability of Stratospheric Sudden Warming of 2013
SPARC-SNAP TeamOm P Tripathi, Andrew Charlton-Perez, Greg Roff, Mark
Baldwin, Martin Charron, Stephen Eckermann, Edwin Gerber, David Jackson, Yuhji Kuroda, Andrea Lang, Ryo Mizuta,
Michael Sigmond, Tim Stockdale, Seok-Woo Son
SPARC - Stratospheric Network for the Assessment of Predictability
(SPARC-SNAP)
SPARC-SNAP Introduction
SPARC – SNAP
A network of research and operational communities aims to answer following questions:
• Are stratosphere-troposphere coupling effects important throughout the winter or only when major stratospheric dynamical events occur?
• How far in advance can major stratospheric dynamical events be predicted and usefully add skill to tropospheric forecasts?
• Which stratospheric processes need to be captured by models to gain optimal stratospheric predictability?
Team LeadersGreg Roff Bureau of Meteorology, AustraliaAndrew Charlton-Perez University of Reading
Steering CommitteeMark Baldwin University of Exeter, UKMartin Charron Environment Canada, Canada Steve Eckermann NRL, USAEdwin Gerber New York University, USAYuhji Kuroda Japan Met Agency, JapanDavid Jackson Met Office, UKAndrea Lang University at Albany, USASeok-Woo Son Seoul National University, S Korea
Om Tripathi University of Reading (Co-ordinator)
(www.sparcsnap.org)
SPARC-SNAP
SPARC-SNAP Activities• A new multi-model experiment to quantify
stratospheric predictability• Stimulate the growth of a community of
researchers interested in stratospheric predictability (workshop, web, newsletters etc).
• A review paper on current understanding of stratospheric predictability (accepted in QJ)
• A SPARC report and peer-reviewed articles on the findings of the experiment.
SPARC-SNAP ProtocolCase -15 -10 -5 0 +5
Phase 1: SSW NH 2013
23/12/2012 28/12/2012 02/01/2013 07/01/2013 12/01/2013
Phase 1: Final Warming SH 2012
05/10/2012 10/10/2012 15/10/2012 20/10/2012 25/10/2012
Run Length 15-30 days
No. of Ensemble members
As many as possible
Phase 0 Current operational forecast for ONE year
Phase 2 TBD (Same as phase I for past cases)
SPARC-SNAP Operational Models and Database
• Met Office, UK (METO)• Meteorological Research Institute (MRI), JAPAN• Naval Research Laboratory, USA (NOGAPS)• Bureau of Meteorology, Australia (CAWCR)• Korea Air Force operational model, Korea Polar
Research Institute, Korea (KOPRI) • ECMWF• Korea Meteorological Administration (KMA),
Korea • Environmental Canada (EC), CANADA
1. Model failed to predict SSW 15 days before the event except some members of few models2. All of the models were able to predict 10 days before the event3. Models find it hard to sustain the eastely after the event
-15 days -10 days
KO
PR
I
EC
MW
F
M
ET
O
NO
GA
PS
M
RI
C
AW
CR
RMS Error
Spread reduces once the model predicted the warming 10 days before the event
Best and Worst Members
• Some members of models have shown vortex weakening or even wind reversal 15 days before the events
• Best members of model are those that approached closest to the zero line wind at 10 hPa
• Worst members are those that were farthest away from the zero wind line
• These two sets are treated separately• Upward component of EP flux (v’T’), and contribution
from different wave components for these sets compared
CAWCR MRI NOGAPS METO KOPRI
Ep
z T
rop
osp
her
eE
pz
Str
ato
sph
ere
U
at
10 h
Pa
60N
EP Flux (Upward component) – ALL Wave NumbersFor initialization before 15 days
Ep
z T
rop
osp
her
eE
pz
Str
ato
sph
ere
U
at
10 h
Pa
60N
CAWCR MRI NOGAPS METO KOPRI
EP Flux (Upward component) – Wave Numbers-1,2,3For initialization before 15 days
Ep
z T
rop
osp
her
eE
pz
Str
ato
sph
ere
U
at
10 h
Pa
60N
CAWCR MRI NOGAPS METO KOPRI
EP Flux (Upward component) – Wave Number-1For initialization before 15 days
Ep
z T
rop
osp
her
eE
pz
Str
ato
sph
ere
U
at
10 h
Pa
60N
CAWCR MRI NOGAPS METO KOPRI
EP Flux (Upward component) – Wave Number-2For initialization before 15 days
Ep
z T
rop
osp
her
eE
pz
Str
ato
sph
ere
U
at
10 h
Pa
60N
CAWCR MRI NOGAPS METO KOPRI
EP Flux (Upward component) – Wave Number-2For initialization before 10 days
Summary• Except a few ensemble members of MRI and METO, none of the models
predicted the splitting by the 15 days lead time. • A significant number of NOGAPS ensemble predicted a clear displacement
type warming 15 days before the event. • When NOGAPS is initialized 5 days before the event, it switched its SSW
type from displacement to splitting. • Detailed EP-flux analyses have shown that models struggle to simulate the
amplification of wave-2 structure in the stratosphere despite being successfully generating wave-2 in the troposphere.
• This is in contrast to the amplification of wave-1 where all the models have shown a significant success in transmitting the wave-1 energy to the stratosphere
• Data is accessible at http://badc.nerc.ac.uk/help/jasmin_workspaces.html• For info about SPARC-SNAP activity and data access: http://www.sparcsnap.org/