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Last Interglacial Experimental Design

Page in progress: this is not the final version! Use the discussion panel at the end of the page for comments

Goal

Run early Eemian, mid-Eemian and glacial inception snap shots. This will allow us to model the response to obliquity maximum (130ka) and minimum (115ka), and near precession optimum for ITCZ shift, ENSO and tropical monsoons (125ka)

Core experiments

130ka, 125ka and 115ka time slices with ocean-atmosphere models. If only one Last Interglacial experiment is carried out, 130ka is the top priority.

Extra experiments

128ka

repeat core and 128ka experiments with equivalent ocean-atmosphere-vegetation models

Ice-sheet reconstruction sensitivity

Reduced Greenland ice-sheet, possibly using the model reconstruction of Otto-Bliesner et al (2006)

Reduced West Antarctic ice-sheet

transient interglacial simulations: 130-125ka (or 130-115ka). Either low resolution model or GCM with accelerated boundary conditions, using transient orbit and trace gases

transient holocene simulations: 8-2ka (or 8-0ka). Either low resolution model or GCM with accelerated boundary conditions, using transient orbit and trace gases

Boundary conditions

130ka (CORE - TOP PRIORITY)

PMIP3	Alternative solution
Orbital parameters	[ ecc = 0.038209 ] - [ obl = 24.242° ] - [ peri-180° = 228.32° ]
Date of vernal equinox	March 21 at noon
Trace gases	[ CO2 = 257 ppm ] - [ CH4 = 512 ppb ] - [ N2O = 239 ppb ] - [ CFC = 0 ] - [ O3 = Same as PI ]
Aerosols	Same as PI
Solar constant	1365 W/m2
Vegetation	Pre-industrial fixed
Ice sheets	Same as PI
Topography and coastlines	Same as PI

Please use the discussion panel to comment this table!

128ka (EXTRA)

PMIP3	Alternative solution
Orbital parameters	[ ecc = 0.039017 ] - [ obl = 24.131° ] - [ peri-180° = 259.65° ]
Date of vernal equinox	March 21 at noon
Trace gases	[ CO2 = 275 ppm ] - [ CH4 = 709 ppb ] - [ N2O = 266 ppb ] - [ CFC = 0 ] - [ O3 = Same as PI ]
Aerosols	Same as PI
Solar constant	1365 W/m2
Vegetation	Pre-industrial fixed
Ice sheets	Same as PI
Topography and coastlines	Same as PI

Please use the discussion panel to comment this table!

125ka (CORE)

PMIP3	Alternative solution
Orbital parameters	[ ecc = 0.040013 ] - [ obl = 23.798° ] - [ peri-180° = 307.14° ]
Date of vernal equinox	March 21 at noon
Trace gases	[ CO2 = 276 ppm ] - [ CH4 = 640 ppb ] - [ N2O = 263 ppb ] - [ CFC = 0 ] - [ O3 = Same as PI ]
Aerosols	Same as PI
Solar constant	1365 W/m2
Vegetation	Pre-industrial fixed
Ice sheets	Same as PI
Topography and coastlines	Same as PI

Please use the discussion panel to comment this table!

115ka (CORE)

PMIP3	Alternative solution
Orbital parameters	[ ecc = 0.041421 ] - [ obl = 22.405° ] - [ peri-180° = 110.88° ]
Date of vernal equinox	March 21 at noon
Trace gases	[ CO2 = 273 ppm ] - [ CH4 = 472 ppb ] - [ N2O = 251 ppb ] - [ CFC = 0 ] - [ O3 = Same as PI ]
Aerosols	Same as PI
Solar constant	1365 W/m2
Vegetation	Pre-industrial fixed
Ice sheets	Same as PI
Topography and coastlines	Same as PI

Please use the discussion panel to comment this table!

Transient 130ka-125ka (EXTRA)

PMIP3	Alternative solution
Orbital parameters	varying, model interpolates values given on a 1k resolution. See values here: http://www.paleo.bris.ac.uk/~ggdjl/pmip/orbit_pmip.out
Date of vernal equinox	March 21 at noon
Trace gases	varying, model interpolates values given on a 0.1k resolution. See values here: http://www.paleo.bris.ac.uk/~ggdjl/pmip/pmip_hol_lig_gases.txt
Aerosols	Same as PI
Solar constant	1365 W/m2
Vegetation	Pre-industrial fixed
Ice sheets	Same as PI
Topography and coastlines	Same as PI

Please use the discussion panel to comment this table!

Notes

Trace gas information was obtained from ice core data, all on the EDC3 chronology. For more information (including figures) and details (including IDL code) of the interpolation, please see the webpage below (including a readme file)

http://www.paleo.bris.ac.uk/~ggdjl/pmip

Orbital values from Berger (1978). Calculated using B78 fortran code downloadable from http://www.astr.ucl.ac.be/index.php?page=AstronomicalInsolationForcing

Initial conditions

PMIP3	Alternative solution
Initial conditions	Branch off PI after adjustement	Same as in PI
Model spin up	Same as in PI

Participating groups

The following groups intend to perform experiments for the Eemian interglacial sub-project

BRIDGE, Bristol, UK

People involved: Joy Singarayer, Paul Valdes, Dan Lunt

We plan to use HadCM3 and HadGEM2 (the version being used for IPCC simulations) to perform the core interglacial OA experiments. HadCM3 will be used for the optional further snap-shot simulations, and FAMOUS for transient Eemian simulations

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