Question 1

________ dunes are linear sand ridges roughly parallel to the prevailing wind direction in areas of moderate sand supply.

Accepted Answer

Longitudinal dunes are formed in areas where there is a moderate sand supply and the wind direction is relatively consistent. They are long ridges of sand that are parallel to the prevailing wind direction. Barchan dunes are crescent-shaped dunes that form when winds blow sand in one direction. Transverse dunes are perpendicular to the wind direction and form in areas with a large sand supply, while parabolic dunes are also crescent-shaped but form when vegetation stabilizes the sand.

Question 2

Rain shadow deserts occur mainly at middle latitudes.

Accepted Answer

Rain shadow deserts are typically found at middle latitudes where prevailing winds blow from west to east (e.g., the Mojave Desert in southwestern United States). As air rises up over a mountain range, it cools and loses moisture, creating a dry region on the leeward side (i.e., the side sheltered from prevailing winds).

Question 3

A dry climate is one in which yearly precipitation is not as great as the potential loss of water by evaporation.

Accepted Answer

In a dry climate, the amount of precipitation is not enough to compensate for the amount of water that is lost through evaporation. As a result, the available water supply is limited and the climate is considered dry.

Question 4

Running water is an important erosional agent in many arid lands despite infrequent rainfalls.

Accepted Answer

Even though rainfall is infrequent in arid lands, when it does occur, the running water can cause significant erosion due to the lack of vegetation and the hard, compacted soil. Additionally, flash floods are also common in arid lands and can cause sudden and intense erosion.

Question 5

Intermittent streams in dry areas of the western United States are called ephemeral.

Accepted Answer

Intermittent streams that only flow in response to precipitation are called ephemeral streams. They are common in dry areas of the western United States, especially in desert regions.

Question 6

The tips of ________ dunes point upwind and commonly result from persistent, onshore winds in certain coastal areas.

Accepted Answer

Parabolic dunes have their tips pointing upwind and are often found in coastal areas where the wind direction is consistent. Unlike other dune types, the vegetation partially anchors the dunes, causing the arms of the dunes to move forward slower than the center, creating a parabolic shape.

Question 7

Assume that the central slip face of a parabolic dune slopes downhill toward the west.What is the direction of the prevailing wind?

Accepted Answer

The answer of Assume that the central slip face of...

Question 8

Deposition of glacial silt from blowing winds near the ice front was responsible for ________.

Accepted Answer

Deposition of glacial silt from blowing winds near the ice front is responsible for loess deposits.

Question 9

About one-third of the Earth's land areas have arid to semiarid climates.

Accepted Answer

According to the Köppen climate classification, which is the most widely used system for classifying the world's climates, around one-third of the Earth's land areas have arid to semiarid climates. These climates are characterized by low precipitation and high evaporation rates, and they include regions such as deserts, steppes, and some parts of Mediterranean regions.

Question 10

Deserts between 30 and 45 degrees of latitude are more extensive in the southern hemisphere than in the northern hemisphere.

Accepted Answer

Deserts are more extensive in the northern hemisphere due to the distribution of landmasses, with major deserts like the Sahara, Arabian, and Gobi located between 30 and 45 degrees of latitude in the northern hemisphere.

Question 11

Which type of dune can be up to 90 metres tall and forms under variable wind directions?

Accepted Answer

Star dunes are known to reach heights of up to 90 metres and form in environments where wind directions are highly variable, allowing the dune to grow upwards rather than in a single directional path.

Question 12

Saltation refers to evaporation of shallow, muddy waters from a playa lake.

Accepted Answer

Saltation is actually a process in which particles such as sediment, sand, and dust are lifted and transported by the wind, causing them to "jump" or "bounce" along the ground. It is not related to the evaporation of water from a playa lake.

Question 13

Steppes are the driest of the true desert lands.

Accepted Answer

Steppes are not true desert lands, although they are dry and often experience droughts. True desert lands have even less precipitation and are characterized by their extreme aridity.

Question 14

________ dunes are long, high, sand dunes parallel with the prevailing wind direction.

Accepted Answer

Longitudinal dunes are formed parallel to the direction of the prevailing wind, and can be very long and high. Choice A, subliminal, is not a type of sand dune. Choice C, latitudinal, is perpendicular to the prevailing wind direction. Choice D, transvestual, is not a recognized term in geology or geography.

Question 15

Assume that a longitudinal dune field has its dune crests oriented north-south, with a few dunes having hooked ends closed to the north, or branching, nearly parallel ridges opening to the south.What is the direction of the prevailing wind?

Accepted Answer

The answer of Assume that a longitudinal dune field has...

Question 16

Loess deposits in the central United States and Columbia Plateau ________.

Accepted Answer

Loess deposits in the central United States and Columbia Plateau originate from silt-sized particles carried by Canadian Pleistocene glacial outwash streams and freshly exposed till.

Question 17

________ are complexly shaped dunes in the Sahara or Arabian deserts, formed in response to different, seasonal, wind directions.

Accepted Answer

Star dunes are formed due to winds blowing from multiple directions, leading to their complex, star-like shape. This is common in the Sahara and Arabian deserts where wind directions change seasonally.

Question 18

Sand is transported by saltation both in running water and by blowing winds.

Accepted Answer

Saltation is a process where sand particles are lifted and carried by a fluid (either water or wind) in a series of short, bouncing movements. This means that sand can be transported by saltation in both running water and blowing winds.

Question 19

Canada's only non-polar desert occurs in the southern Okanagan Valley of British Columbia.

Accepted Answer

The southern Okanagan Valley of British Columbia is home to Canada's only non-polar desert, known as the Osoyoos Desert. It is characterized by hot and dry summers, and receives less than 25 cm of precipitation annually.

Question 20

Multiple, connected, crescent-shaped coastal ________ dunes have tips pointing upwind, towards the beach.

Accepted Answer

Parabolic dunes are crescent-shaped, connected coastal dunes with both tips pointing upwind towards the beach. The shape is formed by vegetation growth and binding of sand, which causes the arms of the crescent to curve backward. Barchan dunes are also crescent-shaped, but they are solitary and found in desert environments. Transverse and longitudinal dunes are linear and not crescent-shaped.

Quiz 18: Deserts and Winds