News from Rossby Centre

1
News from Rossby Centre

• Transient regional climate change simulations
• Erik Kjellström
• Rossby Centre, SMHI
• Presentation at the Rossby Centre day, 4 October
  2006

2
Regionalizations of a transient climate change
Results archived from a GCM-run
CO2
1800
1900
2000
2100
3
A long time perspective Transient simulations of
past climates

• RCA3 at 1.0ox1.0o
• horizontal resolution
• Northern Europe
• Time periods
• 1000-1200,
• 1550-1750,
• 1750-1930
• GCM / Forcing conditions
• ECHO-G
• Changing GHGs,
• volcanic, solar

Moberg et al., 2006
4
Rossby Centre simulations of future regional
climate change
Time slice experiments, completed
Transient simulations, completed
Transient simulations, planned
Transient simulations, being analysed
5
Transient change in annual mean 2m-temperature
compared to 1961-1990

• 1981-2010 2011-2040
  2041-2070 2071-2100

ANN JJA DJF
ECHAM4 A2
Kjellström et al, 2005
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Change in DJF 2m-temperature compared to
1961-1990Adding GCMs and emissions scenarios

• 1981-2010 2011-2040
  2041-2070 2071-2100

ECHAM4 B2 ECHAM5 A1B ECHAM4 A2
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Climate change as represented by indexes
1961-90
2011-40
2041-70
2071-2100
Number of days with snow cover (ECHAM4 A2 on the
boundaries)
8
Looking at interannual and decadal variability
Annual mean temperature in Stockholm
RCA3 with ECHAM4 on the boundaries
9
Stabilizing at 450 ppm CO2-equivalents

• Global mean temperature from CCSM3

Global mean temperature from CCSM3 average
change after stabilization 1K
CO2(eq) 450 ppm
Swedish mean temperature from RCA3 average
change after stabilization 1K
2023
Wyser et al., 2006
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Summary

• Transient regional climate simulations show the
  gradual evolution of climate change.
• Patterns of climate change found at the end of
  the century appear already early in some
  simulations
• but are delayed in others possibly due to
  natural variability.
• Increasing the number of GCMs and emissions
  scenarios is a way to deal with the uncertainties
  in future climate change

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References

• http/www.smhi.se/, go to research, Rossby
  Centre
• Kjellström, E., Bärring, L., Gollvik, S.,
  Hansson, U., Jones, C., Samuelsson, P.,
  Rummukainen, M., Ullerstig, A., Willén U. and
  Wyser, K., 2005. A 140-year simulation of
  European climate with the new version of the
  Rossby Centre regional atmospheric climate model
  (RCA3). Reports Meteorology and Climatology, 108,
  SMHI, SE-60176 Norrköping, Sweden, 54 pp.
• Wyser, K, Rummukainen, M., and Strandberg, G.,
  2006. Nordic regionalisation of a greenhouse-gas
  stabilisation scenario. Report in preparation.
• Moberg, A., Gouirand, I., Wohlfarth, B.,
  Schoning, K., Kjellström, E., Rummukainen, M., de
  Jong, R., Linderholm, H., and Zorita, E., 2006.
  Climate in Sweden during the past millennium
  Evidence from proxy data, instrumental data and
  model simulations. Report in preparation.