Simulation of the „Late Maunder Minimum“ ?

Hans von Storch

Institute of Coastal Research,

GKSS Research Centre

Geesthacht, Germany

København, 17. Oktober 2001

Simulation of the „Late Maunder Minimum“ ?

Hans von Storch

Institute of Coastal Research,

GKSS Research Centre

Geesthacht, Germany

København, 17. Oktober 2001 Inst

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Joint work of

Fidel Gonzalez-Rouco, Ulrich Cubasch,

Stefanie Legutke, Jürg Luterbacher,

Ulrich Schlese, Hans von Storch,

Eduardo Zorita

Joint work of

Fidel Gonzalez-Rouco, Ulrich Cubasch,

Stefanie Legutke, Jürg Luterbacher,

Ulrich Schlese, Hans von Storch,

Eduardo Zorita

1450-2000 simulation

Changing solar forcing and

time variable volcanic load;

greenhouse gases

Spin-up 1450-1550

Forced Simulation

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Late Maunder Minimum

Cold winters and springs, 1675-1710

Late Maunder Minimum

Cold winters and springs, 1675-1710

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Temperature conditions in Switzerland according to Pfister‘s classification.

From Luterbacher, 2001

Climate model used

Atmosphere: ECHAM4

horizontal resolution T30 ~ 300 km at mid latitudes

Ocean: HOPE-G

horizontal resolution T42 ~ 200 km at mid latitudes

increased resolution in the tropics

Model provided as community climate by

Model & Data Group at MPI for Meteorology

and run at German Climate Computing Centre (DKRZ)

and computing facilities at FZ Jülich

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effective solar output

methane (ppb)

CO2 (ppm)

control

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1675-1710vs. 1550-1800

Reconstruction from historical evidence, from Luterbacher et al.

Model-based reconstuction

Late Maunder Minimum

validation

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Air pressure difference, 1675-1710 vs. 1550-1800

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Model as a constructive tool

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I f KGlobal 1675-1710 temperature anomaly

Model as a constructive tool

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Coral-estimated SST for a location off Madagaskar

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validation

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        Galapagos (E-Pacific, 1oS, 90oW, Dunbar et al., 1994):

367 years of coral 18O records from 1587-1953, with annual resolution. The intervals 1660-80, 1710-1800 and 1870-95 were found warmer than “normal”, whereas the intervals 1600-1660, 1680-1700 (LMM) and 1800-25 cooler than on average. 18O increases of about 0.1-0.15‰ heavier during LMM than between 1660-70 and 1705-50 is indicative for a cooling of 0.5-0.75K.

        New Caledonia (SW-Pacific, 22oS, 166oE, Quinn et al., 1998):

335 years of coral 18O records from 1657-1952, with seasonal resolution. The records describe a brief interval of modest cooling in the late 17th century, with an annual mean SST about 0.2-0.3K cooler between 1680-1740 than between 1660-80 and 1740-50

        Great Barrier Reef, Abraham Reef (SW-Pacific, 22oS, 153oE, Druffel and Griffin, 1993):

323 years of coral 18O records from 1635-1957, with bi-annual resolution. More positive 18O values (ca. 0.1‰) during the LMM, are consistent with lower SST’s of about 0.5K

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D'Arrigo and Jacoby.

Reconstructed mean annual temperatures for northern North America Inst

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Simulated differences of ice coverage, in percent, during the LMM event 1675-1710 and the long term mean 1550-1800.

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Model as a constructive tool

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ConclusionsConclusions

• 1675-1715 LMM was a significant winter climate anomalywell documented in Europe

coincident with solar anomalies

• Similar winter anomalies simulated in 1550-2000 AOGCM,forced transiently with anomalous solar output

and volcanic aerosol load

• In the model, the LMM appears as global phenomenonwith maxium effects on the Northern Hemisphere

in particular in the Labrador Sea

• Anomaly results of dynamical interplay of atmosphere and ocean

• Anomaly reminiscent of Great Salt Anomaly

• 1675-1715 LMM was a significant winter climate anomalywell documented in Europe

coincident with solar anomalies

• Similar winter anomalies simulated in 1550-2000 AOGCM,forced transiently with anomalous solar output

and volcanic aerosol load

• In the model, the LMM appears as global phenomenonwith maxium effects on the Northern Hemisphere

in particular in the Labrador Sea

• Anomaly results of dynamical interplay of atmosphere and ocean

• Anomaly reminiscent of Great Salt Anomaly

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LMM?

Dalton?