Great Lakes Weather and Climate

Introduction

• Standing in for a speaker from Environment Canada that was unable to attend at the last minute

• Until yesterday knew almost nothing about weather and climate in the Great Lakes but have been learning fast!

Great Lakes Weather and Climate

• Forecasting weather and projecting climate

• The role of the oceans and Great Lakes

• Great Lakes climate change

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First a bit of history

• Early ability to predict weather constrained by:– Limited understanding of

fundamentals of atmospheric circulation

– Low density of accurate and synoptic observations

– Limited capacity to communicate, integrate and interpret observations

Time Line 1848 - Volunteer Weather Observers recruited

through Smithsonian Institution

1849 - Smithsonian supplies weather instruments to telegraph companies and establishes weather observation network

1870 - President Grant signs bill establishing a national weather warning service within Army Signal Corps

1890 - Cooperative Weather Observer Network established

1891 – Weather service transferred to Department of Agriculture, becomes United States Weather Bureau

1898 – Weather Bureau begins hurricane warning network

1900 - ‘Issacs storm’ kills over 6,000, Weather Bureau establishes regional forecasting centers in response

World Weather Watch

• Established by WMO in 1963

• Creation of a globally coordinated system of observations, data communications, data processing and forecasting

Satellite observations of the atmosphere

TIROS

GOES

Computing

• Meteorology took early advantage of the revolution in computing to deliver routine operational products

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Why are the oceans so important?

Data from Levitus et al, Science, 2001

Because, that is where most of the heat goes

Systematic observation of the global ocean became a goal in 1990

The Global Ocean Observing SystemA joint initiative of:

Technology

• Comprehensive array of technologies for in-situ measurement

57%

100%

40%

82%

43%72%48%21%

100%

Operational Systems

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• 1000 to 1861, N. Hemisphere, proxy data

• 1861 to 2007, Global, instrumental

• 2007 to 2100, SRES projections

Evidence of Climate Change in the Great Lakes Region

• Temperatures are rising, especially in winter.

• Extreme rainfall events (24-hr and 7-day) are becoming more frequent.

• Winters have become shorter.• Spring is coming earlier.• Duration of ice cover is shorter, especially on smaller lakes.

Projected Temperature Increase in the Great Lakes Region (by 2070-99)

Summer

Winter

Higher emissionsLower emissions

Deg F

16

15

14

13

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10

9

8

7

6

Deg F

16

15

14

13

12

11

10

9

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7

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Projected Precipitation Changes in the Great Lakes Region (by 2070-99)

• Doubling of heavy precipitation events

• Seasonal shifts in precipitation -- * More rain in winter and spring (planting season)

* Less rain during the summer and fall growing seasons

• Temperature– Winter 5-12 °F (3-7 °C)– Summer 5-20 °F (3-11 °C)– Extreme heat more common– Growing season several weeks longer

• Precipitation– Winter, spring increasing– Summer, fall decreasing– Drier soils, more droughts

• More extreme events – storms, floods– Could be 50-100% more frequent than now

• Ice cover decline will continue

Projected Climate Changes in the Great Lakes Region by 2100