Tuesday, May 22, 2012


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


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?


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

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
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


L. O. Mearns (USA) and M. Hulme (UK), convening lead
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?)


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 Historical 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 Dynamical downscaling -- increasing GCM resolution,
stretched grids, nested regional models 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) Incorporation of mean changes - the traditional, most
commonly used scenario formation method -
assessment of adequacy for representing climate change - High frequency variability and extremes - daily to interannual 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.


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.



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

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