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Global Hydrology Modelling: Running Multiple Ensembles with the Campus Grid. Simon Gosling Walker Institute for Climate System Research, University of Reading Thanks to Dan Bretherton (Reading e-Science Centre) and Nigel Arnell (Walker Institute). Outline. - PowerPoint PPT Presentation
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Global Hydrology Modelling: Running Multiple Ensembles with the Campus Grid Simon GoslingWalker Institute for Climate System Research, University of Reading
Thanks to Dan Bretherton (Reading e-Science Centre) and Nigel Arnell (Walker Institute)
OutlineThe hydrological model & project backgroundProjected changes in global annual runoffProjected changes in seasonal runoffProjected changes in global water resources stresses
Description of the Hydrological & Project Background
The hydrological model: Mac-PDMMac-PDM is written in Fortran and simulates river flows across the globe on a 0.5x0.5 degree grid.
Input data from global climate models (GCMs):RainfallTemperature HumidityWindspeedCloud cover
The NERC QUEST-GSI projectAim is to examine the global scale impacts of climate change on the hydrological cycle and water resources.If global temperature was to rise by a certain amount, what would the impacts be?Investigate impacts for the following 9 prescribed mean global temperature changes relative to present:+0.5C+1.0 C+1.5 C+2.0 C+2.5 C+3.0 C+4.0 C+5.0 C+6.0 C
The NERC QUEST-GSI projectThe climate data is taken from an ensemble of GCMs to explore the role of climate model structural uncertainty.Source: Collins et al. (2006) Towards quantifying uncertainty in transient climate change. Climate Dynamics 27: 127-147
Running on the campus grid6.05.04.03.02.52.01.51.00.5xxxxxxxxxxxxxxxxxxxxxxxxxxxUKMO HadGEM1xxxxxxxxMRI CGCM232AxxxxxxxxINM CM30xxxxxxxxIAP FGOALS10GxxxxxxxxGISS MODELERxxxxxxxxGISS MODELEHxxxxxxxxGISS AOMxxxxxxxxGFDL CM21xxxxxxxxCSIRO MK5xxxxxxxxCNRM CM3xxxxxxxxCCSR MIROC32MEDxxxxxxxxCCSR MIROC32HIxxxxxxxxCCCMA CGCM31T63xxxxxxxxBCCR BCM20xxxxxxxxNCAR CCSM30xxxxxxxxMPI ECHAM5xxxxxxxxIPSL CM4xxxxxxxxCCCMA CGCM31xxxxxxxxUKMO HadCM3Prescribed TemperatureGCM used to provide climate dataRunning on Linux Desktop:1 run = 3 hours9 runs = 27 hours171 runs = 513 hours (21 days)
On the campus grid:171 runs = 9 hours
Projected Changes in Global Average Annual Runoff
Multiple ensembles for various prescribed temperature changes9 model runs 18 model runs 81 model runs Sign of change varies by GCM
The challenge of summarising the resultsBut there are issues with the ensemble meanThe ensemble mean
The challenge of summarising the resultsNumber of models in agreement
Projected Changes in the Seasonal Cycle of Average Runoff
Mekong Basin&Liard Basin
The Mekong
The MekongChanges in sign vary by GCM.
Magnitude of changes increase with temperature
The Liard
The Liard
Projected Changes in Global Water Stress
Calculating stressesA region is stressed if water availability is less than 1000m3/capita/year
Therefore stress will vary acording to population growth:Stress calculated for 3 populations scenariosSRES A1BSRES A2SRES B2
Stresses calculated for the 2050s with different prescribed warming (0.5-6.0C)
Global water resources stressesHadCM3
HadCM3IPSL CM4CCSR MIROC32HIGlobal water resources stresses
HadCM3IPSL CM4CCSR MIROC32HIGlobal water resources stresses
Global water resources stresses
Global water resources stresses
Global water resources stresses
Global water resources stresses
Global water resources stresses
Global water resources stressesLittle uncertainty due to population change but much due to GCM choice
Summary and ConclusionsUse of the campus grid has reduced run time from 21 days to 9 hoursThis allows a comprehensive investigation of climate change impacts uncertaintyResults demonstrate:GCM structure is a major source of uncertaintySign and magnitude of runoff changes varies across GCMsFor water resources stresses, population change uncertainty is relatively minor
Thank you for your timeVisit www.walker-institute.ac.uk