date: Tue, 17 Jan 2006 16:23:07 -0000
from: "Makin, Janet" <Janet.Makin@uuplc.co.uk>
subject: PRUDENCE range of results
to: gspraggs@anglianwater.co.uk, p.jones@uea.ac.uk, sdw@hrwallingford.co.uk, t.osborn@uea.ac.uk, "EA - Rob Wilby" <rob.wilby@environment-agency.gov.uk>

   Dear all,

   Yes I agree too.  Is there any merit though in the WRONG-HadRM3H as Tim found it lies in
   the middle of the range for the Ouse, while for the Eden it is in the middle during the
   summer drying, but at the top of the range for the winter wetting and thinks we could
   interpret the WRONG-HadRM3H results, including LoS results, as being a typical central
   PRUDENCE scenario?

   Janet

   Janet Makin
   Hydrology Manager
   United Utilities Water PLC
   Water Supply-Demand Team, Thirlmere House Ground Floor, Lingley Mere, Great Sankey,
   Warrington, WA5 3LP
   Tel: 01925 537060  Fax: 01925 464766
   Email: janet.makin@uuplc.co.uk

    -----Original Message-----
   From:   Makin, Janet
   Sent:   17 January 2006 15:16
   To:     Makin, Janet
   Subject:        PRUDENCE range of results

   -----Original Message-----
   From: Spraggs Gerry E [[1]mailto:gSpraggs@anglianwater.co.uk]
   Sent: 16 January 2006 16:29
   To: Rob Wilby; s.wade@hrwallingford.co.uk; p.jones@uea.ac.uk; t.osborn@uea.ac.uk; Makin,
   Janet
   Subject: RE: PRUDENCE range of results

   Dear All,

   I agree with Rob that, as I suggested at the meeting we should discard the earlier results.
   I think it would over-complicate the report to try and include the wrong results as
   sensitivity runs and the time will be better spent focussing on interpreting the correct
   ones.

   I will endeavour to fit in some runs with Tim's new data during the next couple of weeks,
   possibly concentrating on Levels of Service yield because Steve's model is less developed
   in that area.

   Best Regards

   Gerry

   -----Original Message-----
   From: Rob Wilby [[2]mailto:rob.wilby@environment-agency.gov.uk]
   Sent: 16 January 2006 16:09
   To: Spraggs Gerry E; s.wade@hrwallingford.co.uk; p.jones@uea.ac.uk; t.osborn@uea.ac.uk;
   Janet.Makin@uuplc.co.uk
   Subject: Re: PRUDENCE range of results

   Dear All

   Looking at Tim's plots, I'm now of the view that we simply discard the earlier results
   rather than complicate life.

   Gerry and Janet's historic runs are clearly still of immense value for assessing the
   systems' behaviour over the last 200-yrs and for checking the realism of Steven's
   'emulator'.

   The case for analysing the future runs using the spreadsheet method is readily made in
   terms of: 1) consistency between regions; 2)

   speed/efficiency for multiple runs and 3) potentially, sensitivity testing. How does
   everyone else feel about this.

   Tim - assuming that everyone is content with the above, it would be good to have an
   amendment to your plots removing the three wrong runs. Your expanded set of GCM-RCM
   combinations certainly helps place our scenarios in a broader context.

   Cheers, Rob

   >>> Tim Osborn <t.osborn@uea.ac.uk> 01/16/06 02:45pm >>>

   Dear Rob, Janet, Gerry, Steven and Phil,

   please find attached a graphic showing the range of precipitation results from the PRUDENCE
   set of regional climate model simulations. In addition to the 3 wrong scenarios, plus my 3
   corrections that I'd already completed, I downloaded and analyzed results from a further 12
   GCM-RCM combinations - please see the key, with the driving GCM listed first, followed by
   the RCM and the ensemble member (1 in all cases, except for HadAM3H-HadRM3H-M3, where the
   M3 indicates that I used the mean of the 3 ensembles members used for the UKCIP02
   scenarios, rather than the PRUDENCE data).

   The top three in the list are the correct data that we should be using.  They do span the
   PRUDENCE range fairly well (the range of all correct RCMs is shaded pale orange), as
   originally planned (e.g., in summer, ARPEGE (red) is near the top of the range with only
   moderate decreases in precipitation, and HadRM3H (dark purple) is near to the

   bottom of the range with strong decreases).

   The wrong data (black) lie partly within the PRUDENCE range.

   WRONG-HadRM3H (diamonds) lies in the middle of the range for the Ouse, while for the Eden
   it is in the middle during the summer drying, but at the top of the range for the winter
   wetting.  I think we could interpret the the WRONG-HadRM3H results, including LoS results,
   as being a typical central PRUDENCE scenario.

   WRONG-HIRHAM (squares) tend to be near the top of the PRUDENCE range (wetting or less
   drying), though the only critical departure is the huge increase in December precipitation
   for the Ouse.  The WRONG-HIRHAM results could only be interpreted as a sensitivity case,
   outside the PRUDENCE range, but included in the analysis as an

   example of stronger winter increases in precipitation than simulated by the available
   RCMs.  For the Ouse, the fractional change in precipitation averaged over October-March is
   1.41 (i.e. 41% increase - the huge December value is ameliorated in the 6-month winter
   mean).  It seems valid to include a sensitivity case like this - a 41% increase in winter
   precip by the 2080s under a fairly high emissions scenario cannot be discounted - the old
   NIES GCM shown in UKCIP02 had a >60% increase for this case, see fig 28 of UKCIP02.

   WRONG-ARPEGE (triangles) are clearly outside the PRUDENCE range in summer, especially for
   the Ouse.  The WRONG-ARPEGE results could only be included if interpreted as a clear
   departure from the range of possibilities indicated by the PRUDENCE RCMs.  Note that the
   weak winter increases for the Ouse (below the PRUDENCE range in December) might explain why
   yields weren't found to increase as much as the increased summer rainfall might have led us
   to expect.

   [Sorry to focus on the Ouse in my discussion above - it's just that the errors are larger
   there.]

   I hope this figure proves useful to the steering group in deciding how to deal with the
   results from the three wrong scenarios.  Comments anyone?

   Best regards

   Tim

    << File: prud_prec.gif >>

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