Water’s Influence on Weather & Climate

Weather vs. Climate◦Think/Pair/Share

Weather – The condition of the atmosphere at a specific time during the day.

Climate – A region’s generalized weather patterns, averaged over several decades.

Water’s Influence on Weather & Climate

Large bodies of water have a moderating effect on the climate of the nearby region

◦Timmins, ON - 17°C in Jul, -18°C in Jan

◦Victoria, BC - 16°C in Jul, 5 °C in Jan

What do you notice about the temperature in Timmins vs. BC? *note – they are along the same line of latitude

The Moderating Effect

Water has a higher heat capacity than land or air – takes longer to absorb heat, and longer to release heat◦Heat capacity – Ability of a material

to absorb heat

The Moderating Effect

Effect:◦Day & Summer: Land gets hotter

than water; warm air on land rises, cooler air from water blows in to replace it Result: Cooler summers

The Moderating Effect

Effect:◦Night & Winter: Water cools slower

than land; warm air over water rises and cooled air over land moves in Result: Milder winters

The Moderating Effect

The Moderating EffectA helpful hint:

◦At your cottage, which way does the fire blow during the day? At night?

A microclimate is an area with a localized climate variation that differs from the larger climate around it◦Ex. Point Pelee, ON – Sticks out into

Lake Erie◦Ex. A greenhouse

Microclimates

Farmers living close to the Great Lakes experience a much longer frost-free period than farmers in other parts of Ontario

The warmer air from the lakes keeps nighttime temperatures on the shore above freezing longer into the fall

Microclimates & Farming

Northern hemisphere - 39% land, 61% ocean

Southern hemisphere - 19% land, 81% ocean

Greater moderating effect on southern hemisphere’s climate

Water & Global Climate

Coastal regions and other regions located near a large body of water tend to have more precipitation than regions further inland. ◦Why?

As air travels across the water, it picks up a large amount of moisture (water vapour)

Results in more precipitation (rain & snow) Coastal Storms – Hurricane Katrina

Water and Precipitation

Water’s Influence on Weather & Climate

Read and complete workbook pages 158-160

In-class Assignment – Tuesday, October 25th