Chapter 5

Front 1

Advection

Back 1

A process by which a mass of air moves to a new location, bringing its properties, such as temperature or moisture content along with it.

Front 2

Air Pressure

Back 2

The force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of Earth.

Front 3

Anticyclone

Back 3

A center of high atmospheric pressure where upper troposphere air spirals down to the surface and diverges outward.

Front 4

Coriolis Force

Back 4

An effect of the Earth’s rotation that acts to deflect any object moving over its surface from a straight line. ( right in northern hemisphere, left in southern hemisphere)

Front 5

Cyclone

Back 5

A center of low atmospheric pressure where surface air converges into a spiral and is uplifted to the upper troposphere.

Front 6

Equatorial Low-Pressure Trough

Back 6

The zone of rising warm air and low pressure centered more or less over the equator and situated between the two belts of trade winds.

Front 7

Friction Force

Back 7

The force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.

Front 8

Geostrophic Winds

Back 8

Wind at high levels above the Earth’s surface moving parallel to the isobars, at a right angle to the pressure gradient.

Front 9

Intertropical Convergence Zone (ITCZ)

Back 9

A zone of convergence of air masses along the equatorial trough.

Front 10

Isobar

Back 10

A line on a map drawn through all points having the same atmospheric pressure.

Front 11

Jet Stream

Back 11

A high speed airflow in a narrow band within the upper air westerlies and along certain other global latitude zones at high altitudes.

Front 12

Land-Sea Breezes

Back 12

A local wind blowing from land to water during the night.

Front 13

Monsoon

Back 13

A seasonal wind in southern Asia formed by southwesterly flow across the region, which draws the ITCZ well to the north, changing the pressure pattern with the seasons (wet monsoons in summer and dry monsoons in winter).

Front 14

Mountain-Valley Breezes

Back 14

The daytime movement of air up the gradient of valleys and mountain slopes; alternating with nocturnal valley winds.

Front 15

Polar Easterlies

Back 15

The dry, cold prevailing winds that blow from high pressure areas of the polar highs at the north and south poles towards low pressure areas within the westerlies at high latitudes.

Front 16

Polar High-Pressure Cells

Back 16

Located at 90 degrees north/south and are extremely cold and dry. Winds move away from the poles in an anticyclone which descend and diverge to form the polar easterlies.

Front 17

Pressure Gradient Force (PGF

Back 17

The force which results when there is a difference in pressure across a surface. (from high to low)

Front 18

Rossby Waves

Back 18

Horizontal undulations in the flow path of the upper-westerlies; also known as jet stream disturbances.

Front 19

Subpolar Low-Pressure Cells

Back 19

Located at 60 degrees north/south and features a cool, wet weather. Caused by the meeting of cold air masses from higher latitudes and warmer air masses from lower latitudes.

Front 20

Subtropical High-Pressure Cells

Back 20

Located between 20 degrees north/south and 35 degrees north/south, it is a zone of hot, dry air that forms as the warm descending air from the tropics becomes hotter.

Front 21

Thermohaline Circulation

Back 21

Refers to a part of the large scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.

Front 22

Trade Winds

Back 22

Surface winds in low latitudes that move air toward the equator, blowing from the northeast in the northern hemisphere or the southeast in the southern hemisphere.

Front 23

Upwelling Current

Back 23

Wind-driven motions of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient depleted surface water.

Front 24

Westerlies

Back 24

Winds produced as air spirals outward and poleward from subtropical high pressure cells, producing southwesterly winds in the northern hemisphere and northwesterly winds in the southern hemisphere.