MPI ESM Project Super Volcano

Claudia Timmreck, Hauke Schmidt,

and

super volcano project group

31 May 2007

What is a super eruption ?

Super eruptions “are defined to be those eruptions yielding in excess of 1015kg of products (>150 times the mass of the 1991 eruption of Mt. Pinatubo)” (Mason et al, 2004).

Super eruptions are estimated to occur with a minimum frequency of 1.4 events/Myr (Mason et al, 2004), but in Earth history there were episodes with higher frequency.

Historic super eruptions

Toba:

The super eruption of the Indonesian volcano Toba 71-73 ± 5 ka BP (Rose and Chesner, 1987; Oppenheimer, 2002) was the largest known Quaternary eruption

Yellowstone:

Three super eruptions at Yellowstone are known: the Huckleberry Ridge Tuff eruption with an volume of erupted material of 2500 km3 2.1 Ma ago, the Mesa Falls Tuff eruption with 280 km3 erupted material 1.3 Ma ago and the Lava Creek Tuff eruption with a volume of 1000 km3 640000 years ago (e.g., Smith and Siegel, 2000).

Further possible sites for super volcanos:

Phlegrean Fields west of Naples, Lake Taupo (NZ), ….

These eruptions spread volcanic ash over large parts of the North American continent, covering up to 1/3 of the continent with silicate ash of at least 10 cm depth.

Yellowstone Volcanic System

Why study super volcanic eruptions?

Global scientific questions What would be the global impact of a present day Yellowstone

eruption (USA) or an eruption of the Phlegrean fields (Italy) ?

-> Advices for environmental, economic social and political consequences

Was the Young Toba Tuff eruption (74±2kyr BP) responsible for a bottle neck in human population around 70 kyr BP ?

Can super volcanic eruptions trigger ice ages ?

This project should help to understand past climate changes.

Why study super volcanic eruptions?

Super volcanos constitute extremely strong forcing to all compartments of the Earth system:

• Changes in surface albedo and atmospheric radiation • Direct effect on vegetation• Massive global cooling over several years (decades) -> Impact on

vegetation e.g tropical rainforest• Stratospheric warming• Changes in atmospheric circulation (AO) and chemical composition (e.g.

ozone depletion)• Changes in sea level and ocean heat content• Impact on the carbon cycle (e.g. change in NPP, marine bioproductivity)• Impact on water cycle (e.g. reduced tropical precipitation)

This project should help to understand the feedback mechanisms of the Earth system.

Impact of Large Tephra Deposit on Vegetation and Climate

Impact of Large Tephra Deposit on Vegetation and Climate

Tephra (Greek: ash): Fragments of rock and magma ejected from volcanic eruptions, ranging in size from <2mm to >1m.

Effect of tephra deposits on vegetation and surface:• Dying of vegetation• Change of surface fluxes

(canopy/ground - air)• Change of surface albedo• Change of surface and soil

hydrology These changes will have large and

potentially long-lasting impacts on weather, climate and the CO2 cycle on continental and even global scales.

We use the MPI Earth System Model including ECHAM5 (atmosphere), MPIOM (ocean), HAMOCC (marine biogeoche-mistry) and JSBACH (terrestrial biosphere).

Distribution of Tephra Deposit for a Yellowstone Super-Eruption

Tephra depth after initial deposit Tephra depth 5 years after eruption

Tephra cover fraction after initial deposit Tephra cover fraction 5 years after eruption

(R. Schnur et al., MPI-M)

Preliminary Results, JJA

Difference in LAI Difference in Upward CO2 flux

Difference in Surface Albedo

Differences for JJA taken from three-year averages:(2-4 years after eruption) – (1-3 years before eruption)

10-8 kg/m2/s

(R. Schnur et al., MPI-M)

A coupled simulation with MAECHAM5-MPIOM

Coupled ECHAM5MPIOM T63L47–T63L31 comparison

Nearly uniform warming in the troposphere (below 200hPa), largest in the tropics (~0.5 K). Above 200 hPa, the difference in temperature is dominated by differences in the mean stratospheric circulation,

Reduction in the coupled model temperature bias in the tropopause region and in the tropical stratosphere and upper troposphere. At the high latitudes the bias has changed sign.

ECHAM5/MPIOM-ERA40 MAECHAM5-ECHAM5

significanceMAECHAM5/MPIOM - ERA40

(M. Giorgetta et al., MPI-M)

The Pinatubo test case:Radiative effects

1991 1992

Temperature anomaly at 50 hPa after Mt. Pinatubo

After improvements in the SW scheme, the lower stratospheric temperature response is around 4K that is 3K less than the simulations with original ECHAM5 and is more realistic.

(M. A.Thomas, MPI–M)

„Old“ ECHAM5

Improved ECHAM5

NCEP Reanalysis

The Pinatubo test case:A possible volcanic effect on ENSO

o

During the winters following the three biggest eruptions in the last decades (Agung, 1963; El Chichón, 1982; and Pinatubo,1991) El Niños took place.

Paleo reconstrcutions (Adams et al, 2003) seem to indicate that large volcanic eruptions help to drive the ocean and atmosphere towards a state in which El Niño conditions are favored.

A possible volcanic influence on ENSO

We have carried out a series of volcanic experiments with the coupled atmosphere ocean circulation model, the ECHAM5/MPIOM.

The volcanic radiative forcing is calculated online in the model using a realistic spatial-temporal distribution of aerosol optical parameters derived from satellite observations for the Pinatubo episode.

Nino 3.4 SST anomalies [k]

Case 1, June Case 1, Jan

Case 2, JanCase 2, June

(super volcano group, MPI-M)

Conclusions (Pinatubo-ENSO)

Our model results cannot support the hypothesis from Adams et al. (2003) that volcanoes enhance the possibilty of an El Niño event. Our results point in the opposite direction in accordance with new radiocarbon reconstructions (Druffel et al., 2007).

Ongoing work !!!!!!

Impact on the carbon cycle :• volcanic effect on the net CO2 bonding in the terrestrial biosphere)• Input on ocean biogeochemsitry e.g. Algal blossom (Coupling with

HAMMOC is prepared) Understanding the climate signal of historic eruptions, e.g.

1258, Tambora, less cooling in the temperature proxy as one would expected from the estimated emisssion (together with the MILLENIUM project)

Impact on sea level and ocean heat content „Krakatoa lives forever “

......

A fully coupled ESM simulation of a volcanic super eruption including interactive volcanic aerosol and chemistry

This model will be useful for other issues (geo-engineering, asteroid impacts, nuclear weapons impact, ...)

Next steps

Last but not least

The MPI super volcano group is a MPI-M crosscuting project but it is not for MPI-M members only !

All interested scientists are welcome to work and collaborate with us

Further information:

http://www.mpimet.mpg.de/en/wissenschaft/working-groups/super-volcanoes.html

or contact: claudia.timmreck@zmaw.de