date: Wed, 26 Aug 1998 17:25:39 -0600 (MDT)
from: Linda Mearns <lindam@atd.ucar.edu>
subject: Chap.  13 - Final I hope 
to: m.hulme@uea.ac.uk (Mike Hulme)

Mike, 

Below is what I sent as our final chapter. 
I also included this little intro paragraph on things. 
I hope it is acceptable this time.  

By the way, any info from Schimel regarding the US Assessment 
climate models? 

Cheers, 
Linda 


Below is the new outline fo the chapter on climate change scenario 
development.  

In preparing the new (and it is hoped, final) chapter outline, we  considered 
material prepared in other outlines for comparison. 
We examined other chapter outlines for TAR for WGI and II
and find that the content of our outline is in keeping with the basic 
stucture  and breadth of material covered  in other chapters. 
There remains, however, the issue of the fact that THIS SUBJECT  
HAS NOT BEEN COVERED IN EARLIER ASSESSMENTS. 
In going over chapters in all three Working Groups from the second 
assessment and from the chapter outlines for TAR, it is very clear that 
the point of departure for `assessment' is meant research 
that has appeared since the last assessment, and thus was not covered in 
the earlier assessments.  
It is important to note that this point of departure  does not exist for 
the topic of climate change scenario development. We note that this 
truly does blur the distinction between a `review' and an `assessment' 
in this case. 
For example, 
consider the problem climate modelers would have in constructing 
and writing the current chapter 9 in WGI, if the topic of climate models 
and climate model projections had not been covered in SAR and FAR. 
We hope that the co-chairs of WGI will recognize and give due consideration 
to the unique aspects of this chapter.  It cannot conform completely to 
expectations developed in the context of other chapters that cover material    
already examined in earlier assessments. 


Another issue that must be considered in viewing this outline is 
the fact that where simple climate model results are to be primarily 
discussed has not been determined.  
If it is decided that this discussion should reside in chapter 13, then, our 
outline will have to be expanded and the length of the chapter increased. 

This simple model discussion may also affect the choice of an additional 
lead author. 
We already have a total of five lead authors for a rather short chapter. 
We feel this is probably sufficient if the main discussion of 
simple models resides elsewhere. 



                                                   Final Draft 
                                                   Revised 8/26/98 
                                                                           
                             IPCC WGI Chapter 13 

                     CLIMATE CHANGE SCENARIO DEVELOPMENT   

             L. O. Mearns (USA) and M. Hulme (UK), convening lead 
             authors;
             T. Carter (Finland), M. Lal (India), R. Leemans (Netherlands), 
             confirmed lead authors; 

             B. Pittock (or Roger  Jones) (Australia), possible additional 
             lead author, or a climate modeler (G. Boer or J. Mitchell?)

            Contributors: (suggested) P. Whetton (Australia), 
             Demetrious Gyalistras (Switzerland), 
            M. Semenov (UK), Namasova (Chech Republic), R. Katz (USA)
            D. Wilks (USA), T. Kittel (USA), J. Mitchell  (UK), 
            G. Boer (Canada), Rob Wilby (USA/UK?)
 
 
                         OUTLINE 

13.1   Introduction                                                  
       13.1.1 Definition of climate change scenario  - distinction between 
              climate change projections and scenarios 
       13.1.2 Need for scenarios --  impacts needs driven - specifically 
              what information is needed by impacts researchers
       13.1.3 Background on scenario use in quantitative climate impacts 

(Estimated Length - 1 page)
       
13.2   Sources of information on climate change for scenario development
       (This will be an assessment of the adequacy of these various sources.
        Most of them are still used or have been recently used (past 5 years)).
     13.2.1. Sensitivity analysis 
     13.2.2. Analogue approaches 
     13.2.2.1. Historical 
     13.2.2.2  Paeleoclimate            
     13.2.3. Equilibrium GCM integrations 
     13.2.4. Transient integrations 
     13.2.5. Simple models - from integrated assessment models 

(Estimated Length - 1 page)

13.3  Baseline Climatologies -  assessment of the effect on scenario formation 
     13.3.1. Historical period - effect of its variability on scenario formed 
     13.3.2. Resolution in time and space - density of station network - 
             adequacy for regional representation
     13.3.3  Deltas versus ratios  (i.e., taking differences perturbed 
     minus control,  versus taking ratio of perturbed to  control)
(Estimated Length - 1/2 page)

13.4  Incorporation of Spatial and Temporal Resolution 
    13.4.1. Spatial - need for  varying spatial scales (levels of aggregation), 
            depending upon impacts type -- downscaling -- specific needs 
            for use in impacts assessment - 
             issues of spatial correlation and intercorrelation 
             of variables 
       13.4.1.1  Dynamical downscaling -- increasing GCM resolution, 
                  stretched grids, nested regional models 
       13.4.1.2.  Empirical Statistical Downscaling Methods 
     
    (Note:  coordination with chapter 10 is necessary here). 
 
    13.4.2  Temporal Resolution  (assessment of mean versus variance changes 
             in scenarios)
      13.4.2.1.  Incorporation of mean changes - the traditional, most 
                commonly used scenario formation method - 
                assessment of adequacy for representing climate change - 
      13.4.2.2.  High frequency variability and extremes - daily to interannual 
      13.4.2.3.  Low frequency -- decadal to century 
(Estimated Length 2 pages)

13.6  Measures of Uncertainty 
      13.6.1. Use of multiple GCM results to provide ranges of climate 
              change scenarios, and to show climate change response to 
              range of emission scenarios 
      13.6.2. Signal to noise in changes in climate variables 
               and scaling of A/O GCMS 
      13.6.3  Effect of control run variability 
      13.6.4. Annotation of scenarios  - effect of control run errors - 
               climate model validation for impacts purposes
(Estimated   Length - 2  pages)

13.7  Consistency Among Scenario Components -- 
      (Will assess how successfully scenarios maintain internal consistency 
       of individual components, and issues of inconsistencies arising 
       from taking only certain variables from climate models, and calculating 
       others offline.)                                                
       13.7.1 Consistency of Sea Level Rise, Climate, and Direct CO2 Effects 
       13.7.2 Relationship between off-line vegetation/hydrology impacts 
              calculations and vegetation/hydrology models coupled 
              interactively into climate models, 
              (i.e., assessment of direct use of climate model output)
        (coordination with material in WGII).  

(Estimated Length - 2/3 page)

TOTAL LENGTH -  a little over 7 pages. 


COORDINATION ISSUES -  UNRESOLVED ISSUES 
   
  WG I -  Chap 10 -- Regional Analysis -   technical downscaling, weather 
                   generators, regional validation, regional models 
 
  WG I -  Chap 9  - Climate Model  Projections -- 
                    Where will simple model results go (primarily)? 
                    Where will the scenario ranges come from --  simple 
                    models, AOGCMs, combination  of both? 

  WG II - Chap 3 -  Scenarios -  how much detail about climate change 
                    scenarios will be in here?  What discussion of the 
                    TGCIA scenarios will be in here? 

  WG II -  ?      -  Vegetation/hydrology models incorporated in GCMs

  WG III - Chap on emissions scenarios - relates to our uncertainty section


Coordination with following individuals related to above issues: 
N. Nakicenovic, J. Mitchell, T. Carter, M. Hulme, L. Mearns, R. Leemans,  
F. Giorgi, H. Von Storch.

                   


END           



-- 


******************************************************************************
   Dr. Linda O. Mearns                              Phone: 303 497 8124 
   Scientist                                          Fax: 303 497 8125 
   Environmental and Societal Impacts Group           e-mail: lindam@ucar.edu
   NCAR P.O. Box 3000 
   Boulder, CO  80307 

