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/