Alaskan Tundra: Key Knowledge

Question 1

Outline the location of the Alaskan tundra, from southern to northern limits.

Answer 1

From the Northern edge of coniferous forest to the Arctic Ocean.

Question 2

What is the significance of the 10 degree July isotherm?

Answer 2

Climatic limit of tree line.

Question 3

Mean temperatures are below..?

Answer 3

-15 degrees.

Question 4

For how many months does the tundra have negative heat balance, with average monthly temperatures below freezing?

Answer 4

8-9 months.

Question 5

Which part of the ground is not permanently frozen during the Arctic Summer?

Answer 5

Active Layer.

Question 6

True or false: There are times in winter when there is no sunlight at all in 24 hours.

Answer 6

True.

Question 7

Temperatures can plunge below..?

Answer 7

-30 degrees.

Question 8

True or false: Daylight hours are also short in summer?

Answer 8

False.

Question 9

Annual precipitation is less than…?

Answer 9

100mm in most areas.

Question 10

What is the most common form of precipitation?

Answer 10

Snow.

Question 11

Absolute humidity is high or low due to low temperatures?

Answer 11

Low.

Question 12

What is the length of the growing season due to limited daylight hours and low temperatures?

Answer 12

3 months.

Question 13

What is the sun’s energy used up for, leading to low temperatures at ground level?

Answer 13

Melting snow using latent heat.

Question 14

True or false: There is a significant convention in summer when the ground warms up and the active layer of permafrost melts?

Answer 14

False: Ground temperatures still remain low so low convection.

Question 15

Why is there limited groundwater and soil moisture stores? What flows are inhibited?

Answer 15

1. Permafrost is a barrier.
2. Infiltration, percolation, soil moisture recharge, groundwater flow.

Question 16

Why is there a sharp increase in river discharge in spring?

Answer 16

1. Thawing of active layer.
2. Melting of accumulated snow and ice layer.

Question 17

What is the minimum and maximum discharge of Yukon River?

Answer 17

1. Minimum: 340 cumecs.
2. Maximum: 24,600 cumecs.

Question 18

Two reasons why permeability is low in the Alaskan tundra?

Answer 18

1. Extensive permafrost.
2. Impermeable precambrian metamorphic and igneous rock.

Question 19

How many lakes are there in Alaska?

Answer 19

3 million lakes.

Question 20

Where are the wetlands in the Alaskan tundra?

Answer 20

1. Yukon river valley.
2. Deltas.
3. Coast esp off Bering Sea.

Question 21

Explain why there are extensive wetlands, ponds, and lakes on the tundra during summer?

Answer 21

1. Permafrost impedes drainage increasing surface water storage.
2. Ancient rocks underlie the tundra. These have been eroded and weathered over millions of years, forming gentle, undulating plains.
3. Flat relief reduces the speed of the overland flow through/ through flow in the active layer.
4. Chaotic glacial deposits impede drainage, leading to waterlogging in Summer.