PRECIS Providing REgional Climates for Impact Studies The Hadley Centre regional climate modelling system

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PRECISProviding REgional Climates for Impact
StudiesThe Hadley Centre regional climate
modelling system
A presentation to the UNFCCC workshop on
non-Annex 1 national communication preparation
guidelines by Richard Jones, Met Office Hadley
Centre, UK 8 April 2003
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Outline

• Background Motivation and PRECIS overview
• PRECIS components and their application
• Future climate scenarios available from PRECIS
• Applying PRECIS in impacts assessment
• Limitations of PRECIS and future developments

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Motivation

• UNFCCC requirement to assess national
  vulnerability and plans for adaptation
• UNFCCC requirement to submit National
  Communications
• Both need estimate of impacts
• Impacts need detailed scenarios of future climate
• Scenarios are best produced locally, using expert
  knowledge and increasing ownership

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Predicting impacts
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Who is PRECIS for?

• Government scientists from less developed
  countries involved in vulnerability and
  adaptation studies
• A regional models domain usually encompasses
  several countries, so it is hoped that
  neighbouring countries will collaborate to
  produce ensembles
• It is hoped to draw on local resources, such as
  expertise in local climate
  

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Who funds PRECIS?
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How fast does it go?
Hardware requirements

• PC running under the Linux operating system
• Memory 512MB minimum 768MB recommended
• Minimum 60GB disk space offline storage for
  archiving data
• Simulation speed proportional to chip speed

30 year integration, 100x100 grid points

• T3E (supercomputer) - 1.5 months (36
  Processors)
• PC (Intel P4 2.8 GHz) - 4.5 months

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PRECIS PC system components
Domain Scenario Period Diagnostics
Run PRECIS
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PRECIS components full list

• User-interface to set up RCM experiments
• The latest Hadley Centre RCM
• Data-processing and graphics software
• Boundary conditions from latest Hadley Centre GCM
• Training course and materials
• PRECIS website and helpdesk

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What is a Regional Climate Model?

• Comprehensive physical high resolution climate
  model that covers a limited area of the globe,
  usually including the atmosphere and land surface
  components of the climate system, and containing
  representations of the important processes within
  the climate system (e.g., cloud, radiation,
  rainfall, soil hydrology).

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Regional Climate Models (RCMs)

• Limited area models driven at the boundaries by
  GCM observed boundary data.
• Resolution of 50km

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Boundary conditions

• Requests through
• PRECIS website
• helpdesk

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Training course and supporting material

• Training in the use of PRECIS will focus on
• Background science including uncertainties
• Interpretation of PRECIS results by regional
  experts
• Construction of regional climate change scenarios
• Building capacity in countries/regions using
  PRECIS
• PRECIS will be supplied with
• a workbook covering the background science,
  system description and the uses and limitations
  of PRECIS
• a technical manual explaining technical details
  about the system and how install and to use it

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Support and follow-up

• Helpdesk
• email, phone
• web-based discussion
• Website
• news
• updates
• datasets
• resources
• Collaboration/workshops

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Applications of RCMs

• Regional detail when simulating current climate
• Realistic detail in climate change predictions
• Resolution of islands, smaller countries e.g.
  Italy
• Realistic simulation of extreme events
• Provides comprehensive data for impact models

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WINTER PRECIPITATION OVER BRITIANObserved, and
simulated with RCM and GCM
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SIMULATION OF A TROPICAL CYCLONEin the PRECIS
regional climate model
Global climate model Regional climate
model
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WINTER DAILY RAINFALL OVER THE SW CAPE, SOUTH
AFRICA
SW Cape winter rainfall Observed - red, GCM -
green, RCM - blue
lt0.1 0.1-5 5-20 20-30 30-40
gt40 mm/day
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CHANGES IN MONSOON PRECIPITATION between the
present day and the middle of the 21st century
Global climate model Regional climate model
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SUMMER TEMPERATURES in the 2080scompared to the
present day, due to A2 emissions
Global climate model Regional
climate model
Climate on islands changes very differently to
the surrounding Mediterranean Sea, and can only
be predicted using an RCM
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Future climate scenarios available from PRECIS

• PRECIS can provide
• climate scenarios for any region
• an estimate of uncertainty due different
  emissions
• an estimate of uncertainty due to climate
  variability
• Data available from PRECIS
• comprehensive for atmosphere and land-surface
• grid-scale box average quantities
• maximum time resolution one hour

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CO2 EMISSIONS PROFILESunder IPCC SRES scenarios
Source IPCC
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GLOBAL TEMPERATURE RISE due to four SRES
emissions scenarios
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Applying PRECIS in impacts assessments

• Obtain current state from impacts model via
• a) observed data e.g. as used in model
  validation
• b) RCM control data
• Obtain future state from impacts model using
• RCM climate changes (in means, variability, etc)
  applied to observed data (compare with a)
• RCM future climate data directly (compare with b)

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BAY OF BENGAL CYCLONE simulated by the PRECIS
regional climate model
Resulting storm surge simulated using the
Proudman Oceanographic Laboratory model
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CHANGE IN ANNUAL SURFACE RUNOFFbetween today and
the 2080s, for A2 emissions
Southampton University hydrological model
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Current limitations of PRECIS

• 10 year simulations take a month or more
• It is a model hence imperfect, i.e. uncertainty
  due to use of only one RCM is not captured
• Uncertainty due to imperfect driving data (i.e.
  from only one GCM) is not captured
• Resolution of 50km or 25km insufficient for some
  impacts applications
• Coastal or marine impacts have to be inferred
  (e.g. storm surges)

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PRECIS treatment of uncertainties

• PRECIS accounts for uncertainties due to
• Future emissions - uses 4 SRES scenarios
• Natural variability - uses initial condition
  ensembles
• PRECIS does not account for uncertainties due to
• The conversion of emissions to concentrations -
  carbon cycle or chemistry (except sulphur cycle)
  not represented
• Uncertainty in the response of the climate system
  - only boundary conditions from 1 GCM are used
• Uncertainty in the detailed climate change - only
  one RCM is used

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CHANGE IN S ASIA SUMMER RAINFALL with PREDICTED
BY NINE GCMs (A2 emissions)
A2 emissions scenario
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CHANGE INWINTERPRECIPITATION
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REPRESENTATION OF THE PHILIPPINESWITH DIFFERENT
MODEL RESOLUTIONS
25km RCM resolution 50km RCM resolution
GCM 300km resolution
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FUTURE DEVELOPMENTS

• Continuously upgraded to new processors
• Ability to run PRECIS RCM from different GCMs
• at least two to be added this year
• relevant cooperation from GCM centres being
  sought
• Intercomparisons of all RCMs being organised
• No plans for PRECIS to incorporate other RCMs
• Resolution of model being improved to 10km
• RCM with ocean component being built

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Final remarks

• You can contact us via
• Email precis_at_metoffice.com
• Tel [phone]
• Fax [phone]
• Web-site for information on PRECIS
• www.hadleycentre.com/models/PRECIS.html