4.11: Review and Additional Resources

Review

Assess your learning. Start with the "Important Terms and Concepts" to ensure you know the terminology related to the topic of the chapter and concepts discussed.

Important Terms and Concepts \(\PageIndex{1}\)

• Air pressure

  the force exerted by the weight of a column of air above a particular location

• Average sea-level pressure

  serves as the division between what we call "high pressure" and "low pressure" at the surface

• High pressure

  values greater than 1013.2 mb

• Low pressure

  below 1013.2 mb

• Wind

  nothing more than the movement of air molecules from one place to the next

• Pressure gradient

  The spacing of isobars indicates the change in pressure over distance

• Coriolis effect

  a mass moving in a rotating system experiences a force acting perpendicular to the direction of motion and to the axis of rotation

• Friction

  The friction imposed on air mechanically slows the wind and diverts its direction.

• Cyclone

  areas of low pressure

• Anticyclone

  areas of high pressure that exhibit nearly circular isobars

• Convergence

  moving towards a point/area

• Divergence

  moving away from a point/area

• Intertropical convergence zone

  The Equatorial trough

• Subtropical high pressure

  Upper air convergence and radiational cooling cause the air to subside in the subtropics. As the air reaches the surface, atmospheric pressure increases forming the subtropical highs

• Subpolar low pressure

  The polar easterlies collide with the westerly wind belt at about 60 N and S creating a broad belt of low pressure

• Polar high

  dome of high pressure created by loss of energy at the poles

• Northeast tradewinds

  the pressure gradient between the high at 30^o N and the low over the equator

• Westerlies

  wind belt

• Polar easterlies

  Air moving equatorward is turned in an easterly direction

• Monsoon

  wind that changes direction with season

• Land/Sea breeze

  created along coasts where land and water create variations in pressure due to differences in the way these two bodies heat and cool.

• Chinook

  a warm dry wind on the leeward side of a mountain

• Mountain/Valley wind

  During the daytime, mountain slopes warm causing the air over the slope to be warmer than the air over the valley at the same elevation. Warming the air causes it to rise upwards creating a valley wind. During the evening, the air chills due to a loss of surface energy to space. The cool dense air moves down slope as a mountain wind.

• Santa Ana wind

  warm and dry wind.

• Upper-level westerlies

  the upper troposphere poleward of 15^o to 20^o latitude there is an average westerly flow

• Upper-level easterlies

  Between 15^o - 20^o north and south latitude; considered to be an extension of the trade winds

• Jet Stream

  a high speed corridor of air responsible for creating and moving large pressure systems through the midlatitudes

• Circumpolar vortex

  The subsidence creates a vast area of low pressure aloft

• Meridonal flow

  transfer of cold air toward the south and warm air toward the north

• Zonal Flow

  edge is flatter, running more west to east in direction

• Warm ocean current

  corridors of warm water moving from the tropics poleward where they release energy to the air.

• Cold ocean current

  corridors of cold water moving from higher latitudes toward the equator

• El Niño

  weakening of the trade winds in the central and western Pacific allows warm water to invade the eastern Pacific. Along the Peruvian coast, the encroaching warm water displaces the nutrient-rich north-flowing cold ocean current causing a decline in fisheries. Today, the phenomenon is known as the " El Niño/Southern Oscillation"

• La Niña

  Cooler than normal ocean temperature in the eastern pacific/Peruvian Coaast region is called "La Niña"

Additional Resources

Use these resources to further explore the world of geography.

• Focus on The Physical Environment: "El Nino's Extended Family" (NASA Earth Observatory)
• Connections: "When the Dust Settles" (NASA Earth Observatory); "The Effects of Globally Transported African and Asian Dust on Coral Reef and Human Health" (USGS)

Multimedia

USGS Public Lecture Series: "Out of Africa--Dust in the Wind" (October, 2009) Description from the site: "Every year, billions of tons of fine desert dust from the Saharan Desert are transported thousands of miles through the atmosphere to the Americas, Europe and the Near East. Living microorganisms and chemical contaminants such as pesticides and metals are carried along with the dust. What biological and chemical contaminants are hitchhiking with the dust and how might downwind ecosystems such as coral reefs and human health be affected?"

"The Blue Planet" (Annenberg/CPB) Planet Earth Series. Scientists aboard the space shuttle study the oceans from above while researchers dive to the depths of the "middle ocean" to view rare life forms. (58:00) Go to the Planet Earth site and scroll to "The Blue Planet". One-time free registration may be rquired.

Web Sites

Ocean (NOAA) National Oceanic and Atmospheric Administration main web site about the ocean.