the canadian climate impacts scenarios (ccis) project is funded by the climate change action fund...

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Downscaling Tools

Introduction to LARS-WG and SDSM

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

LARS-WG stochastic weather generator

( http:\\www.iacr.bbsrc.ac.uk\mas-models\larswg.html )

• Generation of long weather time-series suitable for risk assessment

• Ability to extend the simulation of weather to unobserved locations

• A computationally inexpensive tool to produce climate change scenarios incorporating changes in means and in variability

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

LARS-WG stochastic weather generator

( http:\\www.lars.bbsrc.ac.uk\model\larswg.html )

• Generates precipitation, min and max temperature and solar radiation• Modelling of precipitation events is based on wet/dry series• Semi-empirical distributions are used for precipitation amounts, dry/wet

series and solar radiation• Temperature and solar radiation are conditioned on the wet/dry status

of a day• Temperature and solar radiation are cross-correlated

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Parametric- e.g., WGEN

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Semi-parametric - e.g., LARS-WG

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

LARS-WG

• Model calibration - SITE ANALYSIS• Model validation - QTEST• Generation of synthetic weather data -

GENERATOR

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

SITE ANALYSIS

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

QTESTCompare observed and synthetic data to evaluate LARS-WG performance

Precipitation

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Minimum temperature

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Maximum temperature

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Solar radiation

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Precipitation variability

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Minimum temperature variability

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Maximum temperature variability

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Solar radiation variability

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The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Base scenario file

GENERATORGenerate synthetic weather data: to extend time series, or

for climate change studies

Scenario file

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

GENERATORPrecipitation

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Maximum temperature

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2050s

Minimum temperature

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Days with maximum temperature > 30°C

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Days with minimum temperature < 0°C

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The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Limitations of LARS-WG (and weather generators in

general) ...

• Temporal downscaling only

• Designed for use at individual sites only (no spatial correlation)

• Can only represent events in calibration data set

• Generally underestimate variability

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

SDSM1. A decision support

tool for assessing local climate change impacts

2. Facilitates the rapid development of multiple, low-cost, single-site scenarios of daily surface weather variables under current and future climate forcing

3. Based on a multiple regression-based method

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

SDSM Structure

7 steps:• Quality Control and Data Transformation• Screening of Predictor Variables• Model Calibration• Weather Generation (using observed

predictors)• Statistical Analyses• Graphing Model Output• Scenario Generation (using climate model

predictors)

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Model Verification

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Victoria: Maximum temperature

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1961-1990

CGCM1 GA1

Downscaled

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Tmax > 25°C

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

The Canadian Climate Impacts Scenarios (CCIS) Project is funded by the

Climate Change Action Fund and provides climate change scenarios and related information to the VIA community in Canada

Cautionary Remarks

• SDSM provides a parsimonious technique of scenario construction that complements other methods

• SDSM should not be used uncritically as a “black box” (evaluate all relationships using independent data)

• Local knowledge is an invaluable source of information when determining sensible combinations of predictors

• Daily precipitation amount at individual stations is the most problematic variable to downscale

• The plausibility of all SDSM scenarios depends on the realism of the climate model forcing

• Try to apply multiple forcing scenarios (via different GCMs, ensemble members, time–slices, emission pathways, etc.)