How will Climate Change Affect WeatherPatterns in the Great Lakes Region?

Peter J. SousounisGeography Department

Michigan State University, East Lansing, MI

www.geo.msu.edu/glra

Background Information

Greenhouse gases make our planet habitable

Too much of a good thing can be bad

GCMs are our climatological crystal ball

Recent motivation

Climate Scenarios - Temperature

• Both GCMs (General Circulation Models) indicate a warmer future by the end of the century

• Canadian Model is considerably warmer than Hadley Model

Canadian Model 21st Hadley Model 21st+15.F

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• Both GCMs (General Circulation Models) indicate increased precipitation

• Canadian Model drier than Hadley in Eastern US regions & wetter in Southwestern US and mountainous regions

Canadian Model 21st Hadley Model 21st100%

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Climate Scenarios - Precipitation

CANADIAN HADLEY

Monthly Thickness - Future Conditions

Thickness of the lower half of the atmosphere reflects surface temperature in a large scale way. A thicker atmosphere is a warmer atmosphere.

• Canadian Model shows significant increases in thickness throughout the year by the end of the century

• Hadley Model shows overall smaller changes than Canadian Model• Both Models show greater increases in fall & winter, than spring &

summer

Arctic Blasts - Current Scenario

Current arctic air outbreaks cause daytime temps to be in the single digits and teens as far south as Kentucky.

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Arctic Blasts - Future Scenario

Such air masses will likely be confined to Canada by the end of this century.

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Monthly Precipitation - Future Conditions

• Canadian shows an increase of ~8% in annual precipitation by 2099. Most of the increase occurs during January-June

• Hadley shows an increase of 12%. Most of the increase occurs during July-December

CANADIAN HADLEY

Why Should Precipitation Increase…?

More frequent storms

Slower storms

Stronger storms

Moister storms

More efficient storms

Heavy Precipitation DAYS for Detroit, Michigan

Both models suggest an increase in interannual variability

• Canadian Model shows increases from 6 to 8 days

• Hadley Model increases from 3 to 6 days

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HVY PCN (MM)

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Both models suggest an increase in interannual variability

• Canadian Model shows increases from 160 to 240 mm

• Hadley Model shows increases from 68 to 133 mm

Heavy Precipitation AMOUNT for Detroit, Michigan

CURRENT FUTURE

Precipitation - Hadley Extreme PCN Pattern

The Hadley Model (above) shows a precipitation increase from 23 to 29 mm. The heavier precipitation in both models will likely result from slightly more intense lows and sharper warm fronts.

Both models show similar patterns for the current and future climate scenarios but with lows farther to the southwest. The Canadian Model shows increases from 40 to 47 mm…

Both models show a decrease in cyclones and a reduction in associated windspeed. The Canadian Model shows a big decrease in cyclones from late spring/ mid summer and from late fall/ mid winter. The Hadley Model shows a big decrease in cyclones in winter and a bigger decrease in spring.

CANADIAN HADLEY

Monthly Storms - Future Climate

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HistoricRecord

Hadley Model CanadianModel

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Snow Depth - Historic, Hadley & Canadian

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Snow Depth - Historic, Hadley & Canadian

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Snow Depth - Historic, Hadley & Canadian

Historic Record:

Hadley Model:

Canadian Model:

= >1” Snow Day

# Snow Days - Historic, Hadley & Canadian

Historic Record:

Hadley Model:

Canadian Model:

= >1” Snow Day

# Snow Days - Historic, Hadley & Canadian

Historic Record:

Hadley Model:

Canadian Model:

= >1” Snow Day

# Snow Days - Historic, Hadley & Canadian

Unfortunately, while it may become too warm for snow, it will still be too cold for people to switch to other (typically summertime) recreational activities such as camping, golfing, and bicycling. More people may find themselves stuck at home and there may be more incidences of Seasonal Affective Disorder - a SAD state of affairs indeed.

Peter Sousounis - The Future of Lake-Effect Snow: A SAD Story, Jan-Feb Acclimations: http://www.usgcrp.gov/usgcrp/Library/nationalassessment/newsletter/2000.02/Lakefx.html

A SAD Story…

Future Winter Flow Patterns…

Both models suggest more frequent and intense El Ninos - especially the Hadley Model…

Summary Climate change in the Great Lakes region will be

manifested by changes in winds and storm tracks as well as by changes in temperature and precipitation.

Extreme hot days will occur at least twice as frequently, extreme precipitation events will increase in frequency and intensity. The number of cyclones will decrease by ~15% and windspeeds will decrease by 10%.

Interannual variability will also likely increase.

The magnitudes of the climate changes will likely have significant impacts on ecosystems in the region.