Wednesday, May 2, 2012

3720.txt

date: Mon, 28 Sep 1998 09:28:17 +0100
from: "Noguer, Maria" <mnogueratXYZxyzo.gov.uk>
subject: FW: A quick, late comment on Agenda item one
to: "scenarios," <scenariosatXYZxyzo.gov.uk>



> ----------
> From: Tom Wigley
> Sent: Friday, September 25, 1998 10:47 pm
> To: Peter Whetton
> Cc: Noguer, Maria
> Subject: Re: A quick, late comment on Agenda item one
>
> At 10:48 AM 9/22/98 +1000, you wrote:
> >Dear All,
> >
> >This is a brief follow-up to Mike Hulme's contribution of a few days
> >ago, where he suggested that modelling groups may well be happy to use
> >all four marker scenarios. I agree that this would be best, particularly
> >if it was done using GCMs with a range of sensitivities. In this
> >context, the group may be interested to know that CSIRO would be willing
> >to undertake AOGCM simulations for all four scenarios (once converted to
> >concentrations in an agreed manner) and that this could be undertaken
> >within a reasonable timetable. (However, there is still interest here
> >in the selection of a single scenario for use in ensemble runs.) I also
> >should note that clearing up inconsistencies between scenarios and
> >observed emissions over the period 1990-2000 is seen here as of vital
> >importance.
> >
> >Peter Whetton
> >
> >
> >Peter Whetton
> >CSIRO Atmospheric Research
> >Private Bag No 1, Aspendale, Vic, 3195, Australia
> >Ph +61 3 9239 4535
> >Fax +61 3 9239 4444
> >Email peter.whettonatXYZxyz.csiro.au
> >
>
> Peter,
>
> A fine offer, but I don't think you can do these runs. To do the
> SO4, you need to have a full S cycle. Otherwise you have to
> use 4-D SO4 loadings, or an albedo proxy. For our collaborative
> work, using the ACACIA/NCAR scenarios (which are superior
> to what is on the IPCC table, because we thought of all the
> problems beforehand), we will be handing over the SO4 data
> for you to use. To get these data requires running our model,
> which has full S chemistry, out to 2100. For the IPCC scenarios,
> someone will have to do a similar full-chem run before you could
> run your model -- and, if they did such a run, IPCC would already
> have what you were offering!
>
> There was an indication in an email from Prather that Penner might
> produce the SO4 loadings. I pointed out to him that she cannot do
> this because, to my knowledge, she does not have access to an
> appropriate coupled model. She might think it can be done with an
> equilibrium model, but this would be wrong. Think of 2050 as an
> example. To get the SO4 loadings with an MLO/AGCM requires
> getting the correct (or at least consistent) climate for 2050. To do
> this, in turn, requires using some artificial CO2 or CO2-equiv that
> would give an MLO/AGCM equilibrium climate response that simulated
> the response in 2050 of an OAGCM. In fact, to really do this 'right'
> one would also have to 'fake up' the SO2 emissions! We have thought
> this issue through at great length here, and decided that there simply
> was no adequate MLO/AGCM-based 'short cut' to getting the SO4
> loadings -- which is why we go the full-chem route.
>
> I presume you are going to China. If so, enjoy. I will be at the CMIP
> workshop on Oct 14,15 and will be at CSIRO on the 16th.
>
> Cheers, Tom.
>

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