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IPCC-Overview-Roeckner

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					IPCC experiments: Overview

            E. Roeckner
Max Planck Institute for Meteorology




                IPCC Workshop 29-30 September 2005, Hamburg
   Stragegy for the Fourth Assessment
          Report of IPCC (AR4)

Modelling groups were asked to perform
• Three scenarios (A1B, B1, A2)
• Multiple runs for each scenario

      Sampling of uncertainties w.r.t.
• Scenario assumptions
• Natural variability
• Model formulations (about 20 models)
Experiments                  Years

Pre-industrial control       530

20th century                 1860 - 2000

21st century stabilization   2001 - 2100 (2000 forcing)

Scenarios A1B, B1, A2        2001 - 2100

A1B, B1 stabilization        2101 - 2200 (2100 forcing)

A1B stabilization ext.       2201 - 2300 (2100 forcing)
                         70 (until 2xCO2)
1% per year CO2 increase
                         + 150 years

                         70 (until 4xCO2)
1% per year CO2 increase
                         + 250 years

ECHAM5
                         1978 - 1999
(Observed SST)

ECHAM5/MLO control       100 years


ECHAM5/MLO
                         100 years
CO2 doubling
                Model components

             ECHAM5             Concentrations
Atmosphere    T63L31               (GHG, SO4)




Land         Momentum              ECHAM5
Surface      Heat, Water         + river runoff

                     Coupling interface (PRISM)

Ocean         MPI-OM
Sea ice       1.5°L40
Stability of preindustrial
      control run ?
       Global annual mean
       2m temperature in pre-industrial control run

[°C]

14.5



14.0


                                       0.026 °C / century
13.5
              100      200           300       400
                             years
         Sea-ice area (106 km2)
    NH   15


         10


          5
                 100    200       300   400   years
         20
    SH
         15
Observed
        10
seasonal
range    5

          0
     Global annual mean surface air temperature
[°C]          (deviation from 1961-1990)

                               A1B_1
                               A1B_2
                               A1B_3
              20C_1
              20C_2
              20C_3
              OBS




                                            year
                                 Annual mean
                                 temperature
                                 change

                                 A1B


                                 B1



0   1   2   3   5   10
                         [° C]
Shifting climate zones ?
 Simulated

Climate zones
(classification
after Koeppen)



 Observed
 1961-1990

Climate zones
(classification
after Koeppen)


 A1B
 2071-2100
Precipitation change (2071-2100) minus (1961-1990)
Columns: Amount (mm/month)
Colours: Percent                  (Month = August)
Changes in storms ?


Bengtsson, Hodges, Roeckner
    J. Climate, submitted
Storm track density (DJF 1961-1990)

   Observed          Simulated
Frequency distribution of maximum
storm intensity (NH, DJF 1979-1999)


                ERA40
Changes in the frequency distribution of
 maximum storm intensity (DJF, NH) ?

                 1961-1990




         2071-2100
Changes in the frequency distribution of
   maximum storm intensity (DJF) ?
     East Atlantic     Mediterranean area


                                1961-1990

                                 2071-2100
Changes in mean storm intensity (DJF)
Changes in the frequency distribution
   of tropical storms (MJJASO) ?

          1961-1990

            2071-2100
Stabilization scenarios
Brasseur and Roeckner
Geophysical Research Letters, accepted
Constant concentrations after year 2000
Anthropogenic sulfate emissions = 0 after year 2000

        a)    Surface air temperature
  2.0

  1.5

  1.0

  0.5

  0.0

  -0.5       OBS
    1950           2000          2050     2100
                          Year
                      Summary
(Broad-scale changes at the end of this century)

Amplification of the warming at high northern latitudes
Land-sea contrast (warming over land more pronounced)
Enhanced precipitation at high latitudes and in the tropics
Poleward expansion of the arid climate zones
No overall increase in the intensity of winter storm at
middle northern latitudes, but there are regional shifts
(e.g., enhanced activity in the eastern Atlantic including the
British Isles, southern Scandinavia central and eastern
Europe, and reduced activity in the Mediterranean area)

				
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posted:12/19/2011
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