Predicting global mean temperature

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Predicting global mean temperature
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Developments at ECMWF
Tim Stockdale, WGSIP12

• Merge of monthly forecast into EPS
• Medium-range EPS is now continuous with monthly
  forecast
• Resolution steps down from T399 to T255 after
  10 days
• Hindcasts also have high resolution for first 10
  days
• Forecasting system changes every few months
  hindcasts produced in near-real time.
• Runs to 15 days every day to 32 days only once
  per week
• Ocean coupling switched off for first 10 days
  for the moment
• Experimental runs to 45 days
• A first step towards unified NWP/seasonal
  prediction ??

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Monthly All India Precipitation
Correlation with IMD station data- 1991-2007
VEPS
SEAS3
(Slides from Frederic Vitart)
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Interannual variability of Atlantic hurricanes
1991-2007
Correlation with HURDAT
August September October
VAREPS Seas - Month 1 Seas Month 2 0.77 0.31 -0.03 0.37 0.33 0.23 0.69 0.18 0.18
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Interannual variability of Accumulated Cyclone
Energy 1991-2007
Correlation with HURDAT
August September October
VEPS Seas- Month 1 Seas- Month 2 0.83 0.77 0.69 0.87 0.86 0.34 0.82 0.80 0.77
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Global Scores
2mTm- Ensemble mean correlation with
analysis August 1981-2007
SEAS3- Month 2
VEPS
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Developments at ECMWF

• Seasonal prediction System 4
• New ocean model NEMO
• New ocean assimilation system 3D/4D VAR
• New coupling interface OASIS3
• Better treatment of lakes and sea-ice
• Hope to have improved stratosphere (extra
  resolution, volcanic aerosols, improved gravity
  wave parameterization)
• Consistent land surface initialization
  (stand-alone analysis system)
• (Latest IFS cycle is much more active in tropics,
  generally more accurate, but has problems with
  easterly bias in equatorial winds, at least at
  TL159)

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Developments at ECMWF

• Decadal prediction
• Only as part of EU-funded projects
• ENSEMBLES
• THOR
• COMBINE
• EC-EARTH
• European group adapting the ECMWF model for
  climate change work
• Attempt to keep technical infrastructure
  integrated with ECMWF
• We may get feedback from some aspects of their
  work