PERTURBATION VS. ERROR CORRELATION ANALYSIS PECA

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PACIFIC PREDICTABILITY EXPERIMENT LINKS WITH THE
INTERNATIONAL POLAR YEAR (IPY)
Zoltan Toth
      
Environmental Modeling Center NOAA/NWS/NCEP
USA Acknowledgements Sharan Majumdar,
Yucheng Song, Craig Bishop, Istvan Szunyogh,
Lacey Holland, Tim Marchok, Jean-Guy
Desmarais http//wwwt.emc.ncep.noaa.gov/gmb/ens/i
ndex.html
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OUTLINE / SUMMARY

• LINKS BETWEEN THORPEX IPY
• Both global programs
• THORPEX is weather component of IPY
• Joint field program during IPY
• SCIENTIFIC HYPOTHESES FOR THORPEX-IPY
• Main sources of observational uncertainty over NH
• Main factors supporting / limiting predictability
  over two hemispheres
• NOAAS INTERESTS IN THORPEX-IPY
• Short-Term Arctic Predictability (STAP)
• 3-90 days forecast of high impact weather, sea
  ice, ocean wave, land surface
• PACIFIC PREDICTABILITY EXPERIMENT
• THORPEX-IPY theme
• Complemented by meso-scale studies
• NORTH AMERICAN ENSEMBLE FORECAST SYSTEM

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LINKS BETWEEN IPY THORPEX
International Polar Year (IPY) Multi- and
interdisciplinary international research
experiment 03/2007-02/2009 Study areas of
strongest climate change impact Comprehensive
research in both polar regions Strong links to
the rest of the globe - Theme 3 (of 6) Advance
our understanding of polar - global interactions
by studying teleconnections on all
scales. THORPEX A World Weather Research
Program (WWRP) Accelerate improvements in
skill/utility of 1-14 day weather
forecasts Long-term (10-yrs) global research
program in areas of Observing system, data
assimilation, numerical modeling/ensemble,
socioec. appl. Strong link with operational
Numerical Weather Prediction (NWP)
centers International program under
WMO Planning initiated with discussions about
North Pacific experiment Opportunities for IPY
- THORPEX Collaboration Joint THORPEX-IPY
Observing period Major opportunity for
accelerating observing system design
work Improved weather forecasts for polar
regions IPY activities Scientific
investigations Link between weather and
climate processes Mid-latitude Polar
interactions THORPEX IS THE WEATHER COMPONENT OF
IPY
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SCIENTIFIC HYPOTHESES FOR THORPEX-IPY RESEARCH

• HYPOTHESIS A Initial conditions
• Main sources of forecast uncertainty /
  impediments to extending forecasts to day 14
• Tropical excitation of waves from the Pacific
  ocean, especially from Maritime Continent
• The mid-latitude flow regime over the Pacific
  Ocean
• The polar circulation with episodes of cross
  polar flow
• Assess relative importance of three sources of
  uncertainty their interaction
• What is optimal mix of observations to reduce
  forecast uncertainty?
• What is best way of assimilating relevant data?
• HYPOTHESIS B Numerical modeling
• The level of predictability forecast skill over
  the NH vs. SH are influenced by
• Nature of flow regimes in polar regions
• More symmetric circumpolar vortex with little to
  no cross polar flow over the Antarctic
• Less symmetric vortex with major episodes of
  cross polar flow over the Arctic
• Difference in distribution of continents and
  oceans over two hemispheres
• Much larger contrast between land and ocean
  masses over NH
• Nature of wave guides for tropical to
  extratropical energy transfer
• Better defined / spatially locked wave guide
  (PNA) over NH
• Assess relative role of three factors their
  relationship in
• Supporting and limiting atmospheric
  predictability for

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NOAAS INTEREST IN THORPEX-IPY

• SHORT-TERM ARCTIC PREDICTABILITY (STAP, IPY
  Proposal 798)
• Study variability predictability of Arctic high
  impact
• Atmospheric, ice, ocean, and land surface events
• Their interaction with global processes
• On 3-90 days time scale
• Program elements
• Observing System
• Study effect of supplemental Arctic IPY data on
  NWP skill, including ocean wave sea ice
• Test new satellite in situ platforms/instrument
  s
• Collect adaptive obs. along N-Pacific storm track
  its source region in tropics to improve IPY
  fcsts
• Data Assimilation
• Develop targeting methods for improved high
  impact Arctic events
• Improve assimilation of current future atmos.
  (over ice/snow), sea ice, ocean/land surface
  data
• Contribute to design of new global observing
  system over 2 polar regions in framework of GEOSS
• Numerical Modeling
• Identify diagnose model weaknesses critical for
  polar regions polar-extrapolar interactions
• Improve atmospheric, sea ice, n land surface
  model formulation
• Accelerate testing implementation of Hybrid
  Coordinate Ocean Model (HYCOM) for storm surges

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SHORT-TERM ARCTIC PREDICTABILITY (STAP, 798)

• Principal Investigators
• Satellite data / assimilation
• Jeff Key (NOAA), Chris Velden (SIMSS), John
  LeMarshall (JCSDA)
• Coupled Atmosphere-ice-ocean-land surface
  diagnosis and modeling
• Robert Grumbine, Julian Wang, Mel Shapiro (NOAA)
• Socio-Economic Applications
• James Partain (NOAA), Rebecca Morss (NCAR), Arun
  Kumar (NOAA)
• Connections with other IPY activities
• Cluster 2
• Terrestrial cryosphere, NH (392 - Grumbine)
• Arctic Sea Ice (185, Grumbine)
• Cross-cutting (Shapiro, Toth)
• Cluster 4
• Weather-Climate link (Kumar, Wang)
• THORPEX (Toth, Shapiro)
• Observing Systems (129, 138, 699, 732, Key,
  Velden, LeMarshall)
• Teleconnections (Shapiro, Toth)
• Cluster 5

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SHORT-TERM ARCTIC PREDICTABILITY (STAP, 798)

• NOAA IPY Connections
• IPY activities coordinated by John Calder
• STAP is one of 10 NOAA IPY proposals, linked in
  particular with
• Causes impacts of recent changes in Pacific
  Arctic (157, Calder K. Crane)
• Data Management/Arctic Change Detection (879,
  Florence Fetterer)
• Decision support in Alaska the Arctic (215,
  Juniper Neill)
• Arctic climate modelling (337, Tony Beesley)
• Arctic system reanalysis (179, John Calder)
• Satellite products (600, Jeff Key)
• US Connections
• Pacific Predictability Experiment (PAPEX)
• Led by David Parsons
• Need for agency (NASA, ONR, NSF) wider
  community (univ./private) coordination
• Mesoscale activities may leverage off /
  complement THORPEX-IPY work
• North American Connections
• North American Ensemble Forecast System (NAEFS)
• Improve expand operational product line to
  support use in Arctic

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PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

• Main interest?
• Build around THORPEX goals
• Link up with IPY
• Complement it with meso-scale aspects if there is
  interest
• Field OR laboratory experiment?
• BOTH
• Lab work (Improve DA, NWP modeling, targeting
  Use OSSEs)
• Design field phase
• Generalize field results
• Field work
• Real time test demonstration
• Support IPY activities (lab work cannot achieve
  all on ground)
• Timing?
• Must be driven by IPY, March 2007 February 2009
• Main theme?
• Use THORPEX-IPY Science Hypotheses

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PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

• PROPOSE STUDYING LIFECYCLE OF WAVES ON PAC. STORM
  TRACK
• Western Tropical Pacific (ONR, Canada, Asian
  nations?)
• Energy transfer from tropics to extra-tropics
• Extra-tropical transition of tropical cyclones
• Convection linked with Madden Julian or other
  waves
• Western Extra-tropical Pacific (NOAA, NASA?)
• Initial phase of extra-tropical lows
• Targeted observations with 3-5 day lead time
• Adaptive collection of data
• In situ observations (dropsondes, aerosondes?)
• Complement Winter Storm Reconnaissance (WSR)
  program over Eastern Pacific
• Adaptive processing of data
• Satellite observations (dynamically controlled
  thinning etc)
• Arctic Region (IPY)
• Forecast applications (NAEFS)
• Effect of data on extra-tropical forecasts
• Continental US (NOAA)
• Assess effect of IPY data on forecasts for cold
  air outbreaks etc
• Southern Hemisphere (SH THORPEX partners)

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PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

• STUDY LIFECYCLE OF WAVES ON PACIFIC STORM TRACK
• Tropical wave in ensemble forecasts (13-16 May)
• Connection between NH SH (NCEP PQPF)
• How well predicted? (ECMWF NCEP MSLP ensemble
  mean)
• Midlatitude low, influenced by tropical wave,
  affects polar region (17-23 May)
• ECMWF NCEP MSLP ensemble mean forecast
  verifying analysis
• Connection
• Can targeting with in situ observations
  (dropsondes) help?
• Results from Winter Storm Reconnessaince over
  NE-Pacific
• PAPEX can complement WSR data over NW-Pacific
• Is West Coast of US more exposed to data void
  than rest of US? (Myth)
• Beyond 24-36 hrs, all areas equally exposed to
  data void
• Predictability over West Coast may be higher
• First generation storms hitting coast at end of
  well organized storm track
• Rest of continent affected by 2nd generation
  storms
• ECMWF
• Targeting to improve longer range / second
  generation storms?
• Beyond

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SUMMARY OF WINTER STORM RECONNAISSANCE RESULTS
NORPEX-98 WSR 1999-2005 WSR operational since
2001

• 60-80 of forecasts improved because of targeted
  observations
• 12-hour gain in forecast lead time
• RMS forecast errors reduced by 10-20
• Local improvement similar to that achieved over
  20 yrs (1975-95) due to advances in data
  coverage/quality

Toth et al. (2000)
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WESTERN VS. EASTERN US PREDICTABILITY Winter of
2002/03
There are seasons when predictability is higher
over western US
WSR00
West
East
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Individual Case Comparison
1 denotes positive effect 0 denotes
neutral effect -1 denotes negative effect
VR OBSDATE P T V OVERALL REGION
FHOUR E 20050120 1 1 1 1 82W
,37N 72 W 20050128 1 1 1 1
123W ,40N 24 C 20050205 1 1 1 1
97W ,31N 36 H 20050206 1 1 1 1
155W ,19.5N 24 C 20050206 1 1 1
1 90W ,43N 72 C 20050207 1 1 1
1 90W ,42N 60 C 20050208 1 -1
1 1 90W ,42N 36 AK 20050208 -1 -1
-1 -1 150W ,61N 48 E 20050208 1
0 -1 0 74W ,43N 48 C 20050209 -1
1 1 1 93W ,35N 96 AK 20050210
-1 -1 1 -1 135W ,55N 24 E
20050212 1 1 1 1 88W ,46N 48
W 20050213 1 1 1 1 123W ,38N
48 W 20050213 1 1 -1 1 123W ,38N
60 W 20050213 1 1 -1 1 123W
,38N 72 AK 20050219 1 1 1 1
150W ,61N 48 W 20050220 -1 1 1 1
118W ,34N 48 W 20050221 1 1 1 1
118W ,34N 24 AK 20050222 -1 -1 -1
-1 138W ,58N 24 AK 20050223 -1 1 1
1 140W ,60N 24 AK 20050225 1 1
1 1 140W ,60N 48 W 20050225 1 1
-1 1 123W ,40N 72 E 20050225 1
1 -1 1 75W ,40N 96 E 20050303 -1
1 1 1 86W ,41N 48 AK 20050309
-1 1 -1 -1 130W ,57N 36 H
20050312 1 -1 -1 -1 157W ,21N 24
E 20050313 0 1 1 1 81W ,32N
96 E 20050314 1 -1 -1 -1 79W ,32N
72 E 20050316 -1 -1 -1 -1 78W
,37N 48 W 20050317 1 1 1 1
122W ,38N 48
22 OVERALL POSITIVE
1 OVERALL NEUTRAL 7 OVERALL NEGATIVE
73 improved 23 degraded
OVERALL EFFECT
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Winds
WSR05
Temperature
Humidity
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Precipitation verification

• Precipitation verification is still in a testing
  stage due to the lack of station observation data
  in some regions.

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NORTH AMERICAN ENSEMBLEFORECAST SYSTEM (NAEFS)

• Zoltan Toth, EMC/NCEP/NWS/NOAA, USA
• Jean-Guy Desmarais, MSC/CMC, Canada

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INAUGURATIONCEREMONY
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NORTH AMERICAN ENSEMBLE FORECAST SYSTEM -NAEFS

• Combines global ensemble forecasts from Canada
  USA
• 60 members per day from MSC NWS
• Generates products for
• Intermediate users
• E.g., weather forecasters at NCEP Service Centers
  (US NWS)
• Specialized users
• E.g., hydrologic applications in all three
  countries
• End users
• E.g., forecasts for public distribution in Canada
  (MSC) and Mexico (NMSM)
• Requires moderate additional investment for
• New telecommunication arrangements
• Extra coordination in research/development
  implementations
• Operational implementation March 2006
• Ready to serve IPY and PAPEX community in
  2007-2009

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NAEFS THORPEX

• Expands national/international collaboration
• Mexico joined in November 2004
• UK Met Office, FNMOC, AFWA to join in 2006
• Provides framework for transitioning research
  into operations
• Prototype for ensemble component of THORPEX
  legacy forecast system
• Global Ensemble Prediction System (GEPS), part
  of
• Global Interactive Forecast System (GIFS)

RESEARCH
THORPEX Interactive Grand Global Ensemble (TIGGE)
THORPEX
RESEARCH
Articulates operational needs
Transfers New methods
North American Ensemble Forecast System (NAEFS)
OPERATIONAL
LEGACY (GIFS)
OPERATIONS
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OUTLINE / SUMMARY

• LINKS BETWEEN THORPEX IPY
• Both global programs
• THORPEX is weather component of IPY
• Joint field program during IPY
• SCIENTIFIC HYPOTHESES FOR THORPEX-IPY
• Main sources of observational uncertainty over NH
• Main factors supporting / limiting predictability
  over two hemispheres
• NOAAS INTERESTS IN THORPEX-IPY
• Short-Term Arctic Predictability (STAP)
• 3-90 days forecast of high impact weather, sea
  ice, ocean wave, land surface
• PACIFIC PREDICTABILITY EXPERIMENT
• THORPEX-IPY theme
• Complemented by meso-scale studies
• NORTH AMERICAN ENSEMBLE FORECAST SYSTEM