Wednesday, May 2, 2012

3730.txt

date: Fri, 7 Dec 2001 10:04:28 -0000
from: "Declan Conway" <d.conwayatXYZxyz.ac.uk>
subject: RE: 6-12-01-2001_Hulme
to: "Centre for Water Level Fluctuations" <caspianlevelatXYZxyznet.kz>, "Hulme Mike" <m.hulmeatXYZxyz.ac.uk>

Hi Terry

I guess that for their report Mike and Tim use their pattern scaling method which involves
'taking the difference between a future period (in thier case centred on hte 2080s) and a
control period and then standardising the spatial pattern by dividing by hte global-mean
warming for the particular model experiment and for the appropriate time slice (2080s) the
resulting standardised climate change pattern is thus expressed per degree C of global
warming. These change fields can then be re-scaled for a range of global mean temperature
increases to represent the uncertainty in hte emissions and the climate sensitivity.' (this
is why the time horizon for predicted changes may therefore be altered - because we don't
actually know when certain CO2 concentrations will be reached and how sensitive the climate
system is to a given change in conc.).

This approach is followed for both T and P change.

I think this also answers your second question - for the report the changes will have been
calculated from the difference between the control and the future run from the respective
GCMs - NOT using the baseline.

Okay I hope this is useful - I have received leaflets from Geof Jenkins on hte RCM - I'll
forward these to you - best wishes

Declan.



-----Original Message-----
From: Centre for Water Level Fluctuations [mailto:caspianlevel@kaznet.kz]
Sent: 06 December 2001 04:01
To: Hulme Mike
Cc: Declan Conway
Subject: 6-12-01-2001_Hulme




Dear Mike,


It's a while since we were in contact and this is just a very small query following up your
Caspian Sea Report of many months ago. It is less of a query but more a question of
educating my ignorance.

� When you adjust the model to a standard sensitivity value I assume that the
outputs of, for example precipitation and temperature, also change (close to a pro-rata
amount?). However, would not this automatically change the time horzon of the output. I
find the concept a little perplexing in that if one changes the sensitivity of the model
then one implicitly changes the time of the prediction for that model. Obviously I don't
under the process involved.

� We are finalising the inputs and outputs for the CEH hydrological model and are
having to iron out some anomalies. A comparison of Declan Conway's work on GCM inputs to
the model have been compared with your estimates for the Volga catchment and also similar
work on a hydrological model by the State Hydrological Institute in St Petersburgh. CEH
have suggested that maybe you have calculated your outputs from the GCM control runs rather
than from recorded data such as your CRU Baseline data.and this may account for some
differences.


Sorry to trouble you, the Stage 2 of our project ends today so if a very short and very
quick response were possible it would be appreciated.


Many thanks and Merry Christmas,



Terry

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