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Ensemble simulations of the Last Millennium using an Earth System Model including the carbon cycle

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Title: Ensemble simulations of the Last Millennium using an Earth System Model including the carbon cycle


1
Ensemble simulations of the Last Millennium using
an Earth System Model including the carbon cycle
  • Johann Jungclaus
  • and the Millennium Team

Max-Planck-Institut für MeteorologieKlimaCampus,
Hamburg
2
For the first time, millennium simulations are
carried out in ensemble mode using a
comprehensive Earth System Model (ESM) including
an interactive carbon cycle
3
  • Millennium was made possible by
  • significant progress in the field of the
    terrestrial carbon cycle (JSBACH) and land cover
    change
  • New developments in treating volcanic forcing and
    new natural forcing data sets
  • technical developments in model performance, and
    data post-processing and storage
  • Computational resources as consortial experiments
    at DKRZ

4
The last Millennium climate
IPCC, 2007
  • To what extent are the observed pre-industrial
    climate variations driven by natural forcings
    (orbital, solar, volcanic)?
  • How did the climate system respond to human
    activities (land use changes, industrialization)?
  • What are the relations between forcing, climatic
    states, and variability patterns (AO, ENSO, SAM)?

5
The last Millennium CO2
Gerber et al., 2003
  • Can we simulate a stable carbon cycle over the
    millennial time scale with a complex Earth System
    Model (ESM)?
  • How did the carbon cycle respond to natural and
    anthropogenic disturbances and how important are
    carbon-climate feedbacks?

6
The Earth System Model
7
External forcings
Volcanoes Time dependent information (T.
Crowley, Univ. Edinburgh) on four latitude bands
in terms of aerosol optical depth and effective
radius distribution (talk S. Lorenz)
Land Cover Changes Reconstruction of
anthropogenic land cover changes for the last
millennium (PhD thesis J. Pongratz) Fractional
maps for land use types crop, C3 and C4 pasture
at 0.5resolution combined with potential
vegetation map
8
External forcings solar (TSI)
  • Recent reconsiderations have drastically reduced
    the range of solar variations from the Maunder
    Minimum to present
  • The larger amplitude secular irradiance changes
    of the initial reconstruction are likely upper
    limits of long-term solar irradiation
    variability (Lean, PAGES Newsletter, 2005)

9
List of experiments
  • long (3000yr) control experiment under year 800
    conditions
  • ensemble of five simulations with all external
    forcings (800-2005)
  • ensemble of three with alternative solar forcing
  • Extension of (2) and (3) to the future (IPCC A1B)
  • Single forcing experiments (one each)
  • Sensitivity experiments (e.g. different scaling
    for forcing components)
  • Pilot studies with higher resolution
    (stratosphere) atmosphere model

gt15000 simulated years available through CERA
data base at the WDCC Hamburg
10
Simulation of CO2 evolution
control
full forcing ensemble mean
11
Simulation of CO2 evolution
Mauna Loa
full forcing expt. (monthly means)
12
Observations of CO2 evolution
Ahn, pers. comm., 2009
13
Simulation of CO2 evolution
Solid lines full forcing ensemble E1 (Krivova
solar, 0.1)
dashed lines full forcing ensemble E2 (Bard
solar, 0.25)
Grey shading Overlap of reconstructions (C.
Reick)
14
Competing effects of individual forcings
Atmospheric CO2 concentration
control
Volcanoes only
Land-cover-change only
Global surface air temperature
15
Simulation of CO2 evolution
control
full forcing (annual means)
  • External forcings affect the carbon cycle
    significantly volcanic eruptions lead to an
    decrease, land-use-change to an increase in atm.
    CO2
  • How is the carbon redistributed?

16
Effects of volcanoes on carbon storage
  • atmosphere looses carbon mainly to the land pools
  • Higher uptake by tropical vegetation and soil

17
Effects of volcanoes on carbon storage
Total land carbon inventory Mol (C) m-2
year 1267 minus year 1257, ensemble means
18
Northern Hemisphere temperaturesthe
instrumental period
  • Simulation captures warming trend over 19th/20th
    century
  • Observed multidecadal variations partly due to
    internal variability

19
Northern Hemisphere temperaturesthe last 1200
years
Background shading overlay of reconstructions
(after IPCC, 2007)
solid 5 full forcing expts. (Krivova solar
0.1) dashed 3 full forcing expts. (Bard solar
0.25)
  • Range of variability consistent with
    observations, but LIA cooling less pronounced
    than in reconstruction for 0.1

20
NH (land) temperaturesexperiments mil0012 and
mil0015 differences
Temp. Diff (K)
21
Atlantic Meridional Overturningexperiments
mil0012 and mil0015 differences
AMOC (Sv)
Internal variability on multi-centennial may be
important for climate evolution, such as the
MCA-LIA transition Ensembles are essential!
22
Sensitivity expts. on solar forcing
Sensitivity experiments strong vs. weak solar
variations (black and grey)
23
Sensitivity expts. on solar forcing
Solar 0.25
control
Solar 0.1
24
Sensitivity expts. on solar forcinglead/lag
regression of CO2 and T with TSI
T K/std.dev in TSI
CO2 ppm/std.dev in TSI
Lead/lag time (years)
Lead/lag time (years)
  • Std. dev of (decadal) TSI variations is roughly
    1Wm-2
  • 1 Wm-2 TSI increase makes 0.1K warming and 0.7ppm
    CO2 increase. Can this be identified in
    observations?

25
Millennium and COSMOS
  • Millennium provides to COSMOS
  • boundary conditions for regional studies
  • a well-tested modelling framework (now COSMOS
    1.2) for sensitivity experiments, scenarios, and
    a test-bed for new developments (e.g. isotopes,
    nitrogene cycle)
  • a data base of Millennium simulation accessible
    through CERA (http//cera-www.dkrz.de/CERA)
  • call for analyses projects
  • users are asked to submit a sort summary on the
    planned investigations (similar to PCMDI)

26
  • Titel Interannual to Decadal Climate Variability
    over the North Atlantic Region and its
    Teleconnections in the Millennium Simulations
  • PI Irene Fischer-Bruns
  • Institution Max Planck Institute for Meteorology
  • Add. Investigators Davide Zanchettin, Johann
    Jungclaus, Wolfgang Müller, Daniela Matei
  • Abstract
  • Here we explore the millennium simulations with
    respect to the climate variability in the North
    Atlantic/European (NAE) region on interannual to
    decadal timescales. For this, prominent patterns
    of atmospheric circulation such as the North
    Atlantic Oscillation (NAO) are considered.
    Firstly these patterns are examined whether they
    respond to the forcings applied in the different
    Millennium simulations. Second we consider
    whether the remote response of the NAE climate
    variability to SST variations in the Pacific and
    Atlantic is significantly altered. For this we
    explore the prominent modes of climate
    variability in the Pacific, namely the El
    Niño/Southern Oscillation (ENSO) and Pacific
    Decadal Oscillation (PDO), and how they are
    linked with the NAE region.
  • Publications
  • .

27
Towards higher resolution MILLENNIUM Expt.
  • Originally, we planned to run the Millennium
    experiments with the IPCC AR4 set-up (ECHAM
    T63L31, MPIOM GR1.5). This turned out to be too
    computationaly demanding on the SX6.
  • The last Paleo Model Intercomparison workshop
    (Colorado, Sept. 08) called for a Millennium PMIP
    (and PCMIP)
  • WGCM has adopted the PMIP call and asks for
    Millennium experiments as part of CMIP5
  • Should be carried out with AR5 models or systems
    close to it

28
Towards higher resolution MILLENNIUM Expt.
  • For CMIP5 core activities, presently a system
    with ECHAM5 in T159/L95 and MPIOM at 0.4/L80 is
    developed
  • For CMIP5 long term simulations (TIER1, TIER2),
    such as Millennium, a lower resolution version is
    assembled with ECHAM T63/L47 and MPIOM TP1/L40

29
Millennium and COSMOS
  • Direct simulation of proxies
  • AWI-Bhv d18O Implemention in ECHAM5 almost
    completed, planned for coupled model
  • Carbon isotope composition of carbon dioxide in
    the ESM M. Cuntz (formerly MPI-BGC), Chr. Reick
    (MPI-Met)
  • computes multiple fractionation processes
    occuring during uptake of CO2 from the atmosphere
    by the terrestrial and marine biosphere.
  • Stable as well as radiocarbon activities
  • ? Coordination within COSMOS ?

30
Millennium and COSMOS
  • Effects of solar variation on stratospheric ozone
    and feedbacks
  • Large variability in solar UV ? stratospheric
    ozone ? polar night jet ? dynamical coupling down
    to the troposphere
  • Approach (Hauke Schmidt)
  • Distribute the variation in the solar constant
    unproportionally to the bins of the SW heating
    scheme.
  • Parameterize the stratospheric ozone change
    according to the solar activity.
  • Possible extension
  • Can we go in the direction of an interactive
    (ozone) chemistry while being able to run, at
    least, 100 year time slices (e.g., Maunder
    Minimum vs. control)?

31
Summary/outlook
  • millennium simulations are carried out in
    ensemble mode using a comprehensive Earth System
    Model (ESM) including an interactive carbon cycle
  • Volcanic eruptions stand out as most powerful
    forcing
  • External forcings affect the carbon cycle and
    leave a long-lasting imprint through changes in
    carbon storage
  • Ensembles are essential for the interpretation of
    observed variability
  • Next steps analyses of data set in collaboration
  • Higher resolution model (T63/L47 atmosphere, 1
    ocean)
  • Participate in PMIP3/PCMIP/CMIP5

Thank you for your attention!
32
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33
External forcings volcanoes
Pinatubo
Tambora
Huaynaputina
Krakatau
Time dependent information (T. Crowley, Univ.
Edinburgh) on four latitude bands in terms of
aerosol optical depth and effective radius
distribution
34
External forcings land cover changes
cropland distribution
  • Reconstruction of anthropogenic land cover
    changes for the last millennium (PhD thesis J.
    Pongratz)
  • Fractional maps for land use types crop, C3 and
    C4 pasture at 0.5resolution combined with
    potential vegetation map
  • Based on existing data (1700-1992) and population
    density in earlier times
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