Cold EnvironmentsCold Environments Revision lesson Revision lesson Key question 3.1Key question 3.1

What processes and factors give cold What processes and factors give cold environments their distinctive environments their distinctive

characteristics?characteristics?

ContentContent

Climate descriptionsClimate descriptions What factors result in cold environments?What factors result in cold environments? Erosional processesErosional processes Weathering processesWeathering processes Erosional and Depositional features (maps Erosional and Depositional features (maps

and photos)and photos) Fragile???Fragile??? ExploitationExploitation Sustainable managementSustainable management

Climate descriptionsClimate descriptionsYou will give an You will give an overview of the overview of the climate recognising an climate recognising an element of an annual element of an annual pattern. E.g. ‘A wide pattern. E.g. ‘A wide range in temperature.’ range in temperature.’ You will also recognise You will also recognise a seasonal pattern, a seasonal pattern, such as such as winter/summer.winter/summer.

Have a go at Have a go at CHURCHILL, CHURCHILL, CANADA.CANADA.

Why do we get cold Why do we get cold environments?environments?

What differences do you see?

Why do we get cold Why do we get cold environments?environments?

Why do we get cold Why do we get cold environments?environments?

Why do we get cold Why do we get cold environments?environments?

High Latitude – They receive a relatively small amount of insolation due to the low angle of the overhead sun.

High altitude – Temperatures decline on average of 1 °C per 100m climbed.

Albedo rate – They reflect large amounts of solar radiation. Average absorption is 40%. Dark soils is 90% and Ice, only 10%.

Why is there limmited Why is there limmited precipitation in cold precipitation in cold

environments?environments?

Why is there limmited Why is there limmited precipitation in cold precipitation in cold

environments?environments?

Low air temperatures – Since cold air is only able to hold small amounts of moisture.

High pressure conditions - This reduces the amount of precipitation.

Continentality – In the Arctic, rainfall declines away from oceans as depressions progressively lose moisture.

Rainfall Rainfall

Processes in Glacial Processes in Glacial environmentsenvironments

Freeze Thaw WeatheringFreeze Thaw Weathering

Physical Weathering

1. Rainwater or snow-melt collects in cracks in the rocks.

2. At night the temperatures drops and the water

freezes and expands. 3. The increases in volume of the ice exerts pressure

on the cracks in the rock, causing them to split further open.

4. During the day the ice melts and the water seeps

deeper into the cracks. 5. At night the water freezes again….etc.

Chemical weathering by Chemical weathering by meltwatermeltwater

Especially important on carbonate rocks Especially important on carbonate rocks such as limestone!such as limestone!

COCO2 2 is more soluble in water under colder is more soluble in water under colder temperatures.temperatures.

Forms a weak Carbonic acid.Forms a weak Carbonic acid. As the stream becomes more acidic more As the stream becomes more acidic more

weathering takes place.weathering takes place.

Erosional ProcessesErosional Processes• Plucking

Animation

Erosional ProcessesErosional Processes

AbrasionAbrasion

Scree

Glacial Till

MorainesMoraines

Drumlins

Glacial ProcessesGlacial Processes