To: Fortunat Joos <joos@climate.unibe.ch>

Subject: Re: Millennium Simulations

Date: Mon, 13 Feb 2006 11:20:14 +0100

Cc: Jonathan Overpeck <jto@u.arizona.edu>, Stefan Rahmstorf <rahmstorf@ozean-klima.de>, Anders Levermann <levermann@pik-potsdam.de>, Eva Bauer <eva.bauer@pik-potsdam.de>, plattner@climate.unibe.ch, Eystein Jansen <eystein.jansen@geo.uib.no>, Keith Briffa <k.briffa@uea.ac.uk>

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Dear all,

here is the data from the Climber-3alpha simulations. I know they are

too late, but

perhaps there is still a way to include them. The structure of the files

is the

same as Eva's. The file names correspond to the ones you gave in the

simulation

protocol.

Cheers,

Anders

Fortunat Joos wrote:

> Dear all,

>

> Please find attached an update of the simulation protocol and input

> data description.

>

> Kasper Plattner pointed out that I forgot the obvious. We need of

> course a control run to correct for potential model drift. The readme

> file has been modified accordingly adding a brief description on how

> the control should be done.

>

> I am looking forward to any additional comments. Hope everything is

> clear.

>

> Kasper is currently working to perform the simulation with the Bern2.5CC.

>

> Regards, Fortunat

>

> Fortunat Joos wrote:

>

>> Dear all,

>>

>> I have now compiled the input data set and written a protocol how to

>> perform the runs. It seems to me that it would make sense if we

>> perform the simulations first with the Bern Model and with the

>> Climber 2 model. We can then still decide if we need Climber 3.

>>

>> Please let me know if there are any questions.

>>

>> I could also provide files where the radiative forcing of solar,

>> volcanoes and non-CO2-anthropogenic has been added together.

>>

>> With best wishes,

>>

>> Fortunat

>>

>>

>>

>> Jonathan Overpeck wrote:

>>

>>> Dear Eva and Fortunat - thanks for working on getting things moving.

>>> It seems that the detailed forcing recommendations laid out below by

>>> Fortunat build nicely on what Eva first suggested, and that going

>>> with the forcing series suggested below by Foortunat (and the 6

>>> simulations) is going to be just right for the IPCC AR4 Chap 6

>>> needs. Does everyone agree?

>>>

>>> Thanks Fortunat for preparing/sharing the standard forcing series.

>>>

>>> Best, peck

>>>

>>>> Dear Eva,

>>>>

>>>> We are working on the forcing series and they should be ready by

>>>> the end of the week. Stefan assured us that you can run this

>>>> within a few hours.

>>>>

>>>> What we are preparing are the following series of radiative forcing

>>>> in W/m2:

>>>>

>>>> a) RF from atmospheric constituents (well-mixed GHGs (CO2, CH4,

>>>> N2O, many Halocarbons) tropo and strato Ozone, various

>>>> anthropogenic aerosols) as used in the Bern CC TAR version and the

>>>> TAR (see Joos et al., GBC, 2001; pdf is on my homepage and TAR

>>>> appendix).

>>>> b) volcanic from Crowley, Sci, 2000

>>>> c) solar based on Lean and Bard et al.

>>>>

>>>> For the solar we will prepare 3 combinations:

>>>>

>>>> c1) original serie from Lean (2005) provided to you already

>>>> c2) Bard et al., Be-10 record linearly scaled to match the Maunder

>>>> Minimum Average of Lean-AR4

>>>> c3) Bard et al., Be-10 scaled to a MM reduction of 0.25 permil,

>>>> i.e. the low case in the Bard et, Tellus, publication corresponding

>>>> to the Lean et al, 1995 scaling

>>>>

>>>> For the RF by atmospheric components two cases are foreseen:

>>>> a1) standard case with reconstructed evolution over past 1150 years

>>>> a2) RF kept at 1765 value after 1765, i.e. a simulation with

>>>> natural forcings only.

>>>>

>>>> This will yield in total 6 simulations 3 over the full length from

>>>> 850 AD to 2000 and 3 brach-off simulatons from 1765 with natural

>>>> only forcing.

>>>>

>>>> An important point in IPCC is that things are published, consistent

>>>> among chapters, and it helps if approaches are tracable to earlier

>>>> accepted and approved IPCC work. The arguments for these series are

>>>> as follows:

>>>>

>>>> a) Considering as many components relevant for RF as possible (more

>>>> than just CO2). The series are fully compatible with TAR and that

>>>> the setup is tracable to the TAR for the industrial era increase.

>>>> The same series will be used in the projection chapter 10 for the

>>>> SRES calculation

>>>>

>>>> b) volcanic: a widely cited record

>>>>

>>>> c) solar: c1) and c3) are published series; c2 follows the same

>>>> approach and spirit as used to derive c3, i.e. scaling the Be-10

>>>> serie linearly with a given Maunder Minimum reduction. The impact

>>>> of the 11-yr solar cycle can be looked at in the original Lean-AR4

>>>> serie.

>>>>

>>>> I hope this help.

>>>>

>>>> With kind regards,

>>>>

>>>> Fortunat

>>>>

>>>> Eva Bauer wrote:

>>>>

>>>>>

>>>>> Dear Jonathan, dear Fortunat:

>>>>>

>>>>> Happy New Year!

>>>>>

>>>>>

>>>>> Stefan, Anders and me just have discussed how to set up our

>>>>> CLIMBER2/3alpha runs, to produce something useful for the IPCC WGI

>>>>> chapter 6. This chapter appears to touch the impact on the NH

>>>>> temperature related to low and high solar forcing.

>>>>>

>>>>> For a reasonable comparison, we think two 1000-year simulations

>>>>> differing only by a low and a high solar forcing, conducted with both

>>>>> CLIMBER models, would be ideal. To do so, we would have to extend the

>>>>> solar forcing time series based on Lean (GRL, 2000) and on Wang et

>>>>> al. (2005) distributed in previous e-mails back to the year 1000.

>>>>> This

>>>>> would require some splicing as was done, for instance, by Crowley.

>>>>>

>>>>> I'm thinking of some scaling applied to a series of Crowley (say the

>>>>> data called Be10/Lean splice in Science, 2000) such that the

>>>>> amplitude

>>>>> of the solar variability from the 11-year cycle is conserved after

>>>>> ~1720. I have to check but it appears that the variation in the TSI

>>>>> due to the 11-year cycle contained in the Crowley series agrees

>>>>> perfectly with the 11yr-cycle data in the file based on Lean (2000).

>>>>> Before starting such an exercise I like to ask you what you think

>>>>> about. We would be happy to receive your response quite soon to be

>>>>> able to finish the calculations with our slow model in time for the

>>>>> IPCC report.

>>>>>

>>>>> Could you please also comment on the other forcings we should

>>>>> include,

>>>>> namely the volcanic forcing and the CO2 forcing. For the present

>>>>> study

>>>>> we suggest to use the forcing as in Bauer et al (2000) but omitting

>>>>> the land-use. This means, using the volcanic forcing from Crowley,

>>>>> 2000 and the CO2 forcing based on Etheridge et al 1996 and Keeling

>>>>> and

>>>>> Whorf, 1996. (If you wish we can distribute these data series.)

>>>>>

>>>>> Also, thinking beyond the IPCC study, the model results may become

>>>>> interesting enough to be discussed in a 3-model comparison study!?

>>>>>

>>>>> Looking forward to your reply.

>>>>>

>>>>> Best wishes

>>>>>

>>>>> Eva

>>>>>

>>>>

>>>> --

>>>>

>>>> Climate and Environmental Physics,

>>>> Physics Institute, University of Bern

>>>> Sidlerstr. 5, CH-3012 Bern

>>>> Phone: ++41(0)31 631 44 61 Fax: ++41(0)31 631 87 42

>>>> Internet: http://www.climate.unibe.ch/~joos/

>>>

>>>

>>>

>>>

>>>

>>

>

>------------------------------------------------------------------------

>

>Last Millennium Simulations for IPCC AR4 WG1 Chap 6

>---------------------------------------------------

>

>F. Joos,

>joos@climate.unibe.ch

>18 Januar 2006

>

>OVERVIEW

>--------

>

>A total of 7 simulations is planned.

>

>A control simulation without any forcing

>

>Two millennium-long simulations with solar forcing following Bard et al. with a Maunder Minimum reduction of 0.08 and 0.25 percent in total irradiance and volcanic and anthropogenic forcing included

>

>A simulation from 1610 to 1998 with solar forcing from Wang et al, 2005 and

>volcanic and anthropogenic forcing included

>

>Three simulations from 1765 to 1998 with only solar and volcanic forcing included, but no anthropogenic forcings. These are branches from the above three simulation.

>

>A range of input data files have been prepeared. Each contains a header with additional descriptions of the data.

>

>Solar irradiance has been taken from Bard et al., Tellus, 1999 and from Wang, Lean, Shirley, JAp, 2005.

>

>It is estimated that the Maunder Minimum irradiance is reduce by 0.08 percent

>relative to today and that the present irradiance is 1366 W/m2 from the Wang et al. data.

>

>A case with a Maunder Minimum reduction of 0.08 percent is calculated from the Bard et al. data by scaling the original Bard series appropriately.

>The original Bard series are offset by 1.3 W/m2 in irradiance to bring them to

>a present irradiance of 1366 W/m2. For this excercise we will utilize a Maunder

>Minimum reduction in irradiance relative to today of 0.08 percent and of 0.25 percent (other cases with high MM reduction are included in the files).

>

>Irradiance has been converted to radiative forcing: RF= (IRR-1366)/4*0.7

>

>Volcanic forcing is from Crowley Science, 2000, with albedo factored in (e.g. as for solar forcing). To avoid a cold start of the model, the serie is extended to 850 AD by mirroring the Crowley data from 1001 to 1150 to the period 850 to 1000.

>

>NonCO2 forcing is following TAR (updated for an error in tropo O3 in the TAR).

>

>CO2 is a spline through the Etheridge, JGR, 97 data and the Siegenthaler, TEllus, 2005 data.

>

>

>INPUT FILES DESCRIPTION:

>-----------------------

>

>It is recommended to linearly interpolate between data points.

>

>A1: Solar irradiance and radiative forcing following Bard from 850 to 2000

>

>(Tag description)

>solBard08 2. col: Maunder Minimum reduction of 0.08 percent

>solBard25 3. col: Maunder Minimu reduction of 0.25 percent

>

>Note: data from Bard have been linearlz interplated on an annual time step

>

> files:

> bard00tel_solar_RF_IPCC_Chap6_Joos_11jan06.out

> bard00tel_solar_irradiance_offset-13_IPCC_Chap6_Joos_11jan06.out

>

>

>A2: Solar irradiance and radiative forcing following Wang, Lean, Shirley, 2005

> from 1610 to 2004

>

> annual resolution

>

>Tag: WLS-05

>

> files:

> wang05jastr_lean_RF_IPCC_chap6_Joos_11jan06.out

> wang05jastr_lean_irradiance_IPCC_chap6_Joos_11jan06.out

>

>A3: CO2 concentration in ppm from 850 to 2000

>

> annual resolution

>

>Tag: CO2

> file: co2_850-2000_splined_IPCC_Chap6_Joos_11jan06.out

>

>A4: volcanic forcing after Crowley from 1001 to 1998 AD, extended by artificial

> data from 850 to 1000 AD by mirroring the forcing from 1000 to 1150 to the period 850 to 1000

>

>Tag: volcCrow

>

> annual resolution

>

> file: crowley00sci_RFvolcanic_IPCC_Chap6_Joos_11jan05.out

>

>A5: radiative forcing by non-CO2 agents

>

> annual resolution

>

>Tag: nonco2

>

> files

> rf_nonco2_1yr_1765_2000_individ_IPCC_Chap6_Joos_11jan06.out

> rf_nonco2_1yr_850_2000_IPCC_Chap6_Joos_11jan06.out

>

>

>

>B) SIMULATIONS

>-----------------------

>

>B1. 2 Long simulations from 850 AD to 1998

>

>-------

>

>Simulation B1.1. tag: bard08_volcCrow_CO2_nonCO2_850-1998

>

>Solar forcing from Bard et al. with MM reduction of 0.08 percent, volcanic forcing and forcing from CO2 and other anthropogenic (non-CO2) agents.

>

>Start of simulation 850 AD

>End of simulation: 1998 AD

>initial condition: model spinup for year 850 (or similiar)

>

>Analysis period: 1001 AD to 1998 AD

>start-up period: 850 to 1000 with artificial volcanic data

>

>--------

>

>Simulation B1.2 tag: bard25_volcCrow_CO2_nonCO2_850-1998

>

>as B1.1 but with solar forcing from Bard et al. reduced by 0.25 percent for the Maunder Minimum.

>

>Start of simulation 850 AD

>End of simulation: 1998 AD

>initial condition: model spinup for year 850 (or similiar)

>

>Analysis period: 1001 AD to 1998 AD

>start-up period: 850 to 1000 with artificial volcanic data

>

>--------

>

>Simulation B2: A simulation from 1610 to 1998 restarted from bard08_volcCrow_CO2_nonCO2

>

>With solar forcing from Wang et al., 2005, volcanic forci

>ng and forcing from CO2 and other anthropogenic (non-CO2) agents.

>

>B2 tag: WLS-2005_volcCrow_CO2_nonCO2_1610-1998

>

>Start of simulation: 1610 AD

>End of simulation: 1998 AD

>initial condition: restart from simulation B1.1. bard08_volcCrow_CO2_nonCO2

> at year 1610

>

>Analysis period: 1610 AD to 1998 AD

>

>

>-------

>

>B3: 3 Simulations from 1765 to 1998 with natural forcing only

>

> non-CO2 radiative forcing is kept to zero

> (except for volcanoes and solar)

>

> CO2 is kept at its 1765 value.

>

>Simulation B3.1: tag bard08_volcCrow_1765_1998

>

>Start of simulation: 1765 AD

>End of simulation: 1998 AD

>initial condition: restart from simulation B1.1. bard08_volcCrow_CO2_nonCO2

> at year 1765

>

>Analysis period: 1765 to 1998 AD

>

>-------

>

>Simulation B3.2: tag bard25_volcCrow_1765_1998

>

>Start of simulation: 1765 AD

>End of simulation: 1998 AD

>initial condition: restart from simulation B1.2. bard25_volcCrow_CO2_nonCO2

> at year 1765

>

>Analysis period: 1765 to 1998 AD

>

>-----

>

>Simulation B3.1: tag WLS-2005_volcCrow_1765_1998

>

>Start of simulation: 1765 AD

>End of simulation: 1998 AD

>initial condition: restart from simulation B2. WLS-2005_volcCrow_CO2_nonCO2

> at year 1765

>

>Analysis period: 1765 to 1998 AD

>

>-------

>

>Simulation B4: tag ctrl_850-1998

>

>Control simulation without any forcing

>

>Start of simulation 850 AD

>End of simulation: 1998 AD

>initial condition: model spinup for year 850 (or similiar)

>

>Analysis period: 850 to 1998

>

>

>OUTPUT

>------

>

>I guess minimal output is global and NH mean surface temperature.

>

>

--

Anders Levermann

phone: +49-331-288-2560 Potsdam Institute for Climate Impact Research

fax: +49-331-288-2570 Telegraphenberg A26, 14473 Potsdam, Germany

anders.levermann@pik-potsdam.de www.pik-potsdam.de/~anders

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