which latitudes have sinking air with dry conditions due to atmospheric circulation course hero

The sinking air is relatively dry because its moisture has already been released near the Equator above the tropical rain forests. Near the center of this high-pressure zone of descending air, called the "Horse Latitudes," the winds at the surface are weak and variable.

Full Answer

What is the major atmospheric circulation in the atmosphere?

Major atmospheric circulation involves the Hadley cells, midlatitude or Ferrel cells, and the polar cells in each hemisphere. Warmed and rising air in the Hadley cells rains back on the tropics and moves toward the poles as dryer air. That air meets the dryer equatorward moving air of the Ferrel cells.

What is the driest non-polar location on Earth?

This desert is the driest, non-polar location on Earth. The polar vortex of mid-November, 2013. This cold, descending air (shown in purple) is characteristic of polar circulation. Notice in the figure that the polar regions are also areas of predominantly high pressure created by descending cold dry air, the Polar Cells.

Which direction do low pressure systems like hurricanes rotate?

Because of the Coriolis Effect in the Southern Hemisphere, low pressure systems like hurricanes rotate in which direction? clockwise., Southern Hemisphere, thus low pressure storms rotate clockwise; hurricanes rotate counterclockwise in the Northern Hemisphere. What does saltation do to the surface of sand grains?

Why is the Atacama Desert the driest on Earth?

Rotation of the Earth creates the Coriolis Effect that deflects these moving air masses to produce zones of prevailing winds, the Trade Winds in the subtropics and the Westerlies in the midlatitudes. A combination of latitude, rain shadow, and cold adjacent ocean currents causes the Atacama Desert of northern Chile, the driest desert on Earth.

What is the name of the belts of high pressure at approximately 30° north and south of the equator?

This sinking drier air creates belts of predominantly high pressure at approximately 30° north and south of the equator, called the horse latitudes. Arid zones between 15 o and 30 o north and south of the equator thus exist within which desert conditions predominate.

How does desert weathering occur?

Weathering in deserts takes place just as in other climes only slower because of less water. Desert varnish is a weathering product unique to desert environments. As in more humid climes, water is the main agent of erosion although wind is a notable agent. Large dust storms called haboobs transport large amounts of sediment that may accumulate in sand seas called ergs or finer grained loess deposits. Sand transport occurs mainly by saltation in which grain to grain impact causes frosting of grain surfaces. Sandblasting by persistent winds produces stones with polished surfaces called ventifacts and sculpted bedrock features called yardangs.

What landforms are flat?

Playas are among the flattest of all landforms. Such a dry lake bed may cover a large area and be filled after a heavy thunderstorm to only a few inches deep. Playa lakes and desert streams that contain water only after rainstorms are called intermittent or ephemeral. Because of intense thunderstorms, the volume of water transported by ephemeral drainage in arid environments can be substantial during a short period of time. Desert soil structures lack organic matter that promotes infiltration by absorbing water. Instead of percolating into the soil, the runoff compacts the ground surface, making the soil hydrophobic or water-repellant. Because of this hardpan surface, ephemeral streams may gather water across large areas, suddenly filling with water from storms many miles away.

What is the definition of desert?

Geologically, deserts are defined by a lack of water and arid regions resembling a sea of sand belong to the category of desert called an erg. An erg consists of fine-grained, loose sand grains, often blown by wind, or aeolian forces, into dunes.

What is the weathering product in the desert?

One unique weathering product in deserts is desert varnish. Also known as desert patina or rock rust, this is thin dark brown layers of clay minerals and iron and manganese oxides that form on very stable surfaces within arid environments. The exact way this material forms is still unknown, though cosmogenic and biologic mechanisms have been proposed.

What are some examples of rain shadow deserts?

Examples of rain-shadow deserts include the Western Interior Desert of North America and Atacama Desert of Chile, which is the Earth’s driest, warm desert. Finally, polar deserts, such as vast areas of the Antarctic and Arctic, are created from sinking cold air that is too cold to hold much moisture.

What is the process of desertification?

When previously arable land suitable for agriculture transforms into desert, this process is called desertification . Plants and humus-rich soil (see Chapter 5) promote groundwater infiltration and water retention. When an area becomes more arid due to changing environmental conditions, the plants and soil become less effective in retaining water, creating a positive feedback loop of desertification. This self-reinforcing loop spirals into increasingly arid conditions and further enlarges the desert regions.