Chapter 13: Atmosphere & Climate Change
Section 1:
Climate & Climate Change
Objectives
• Explain the difference between weather and climate.
• Identify four factors that determine climate.
• Explain why different parts of the Earth have different climates.
• Explain what causes the seasons
Climate
• _______ is the _______ weather _______ in an area _____ a long period of time.
Climate
• Climate is determined by a variety of factors that include ______, atmospheric circulation patterns, oceanic circulation patterns, the local geography of an area, _____ ______, and ______ _______.
Climate
• The most important of these factors is ______ ____ the ______.
Latitude
• _______ is the distance ____ or _____ from the _______ and is expressed in degrees.
Latitude
• The equator is located at _° latitude.
• The most northerly latitude is the North Pole, at __° north, whereas the most southerly latitude is the South Pole, at 90° _____.
Latitude
• Latitude ______ ______ climate because the _____ of _____ _____ an area of the Earth receives depends on its latitude.
Low Latitudes
• _____ solar energy falls on areas ____ the equator than on areas closer to the poles.
• The incoming solar energy is concentrated on a small surface at the equator.
Low Latitudes
• In ____ ____ the _______, night and day are ____ about __ _____ long throughout the year.
Low Latitudes
• In addition, ________ are ____ year-round, and there are __ _______ or ______.
High Latitudes
• In regions _____ to the _____, the sun is _______ in the sky, _______ the ______ of ______ arriving at the surface.
• In the northern and southern latitudes, sunlight hits the Earth at an _____ _____ and spreads over a ______ surface area than it does at the equator.
High Latitudes
• ______ _______ ________ near the poles are therefore ______ than they are at the equator.
High Latitudes
• At 45° north and south latitude, there is as much as __ ____ of ________ each day during the ______ and as little as _ ____ of _______ each day in the ______.
High Latitudes
• Near the poles, the sun sets for only a few hours each day during the summer and rises for only a few hours each day during the winter.
• Thus, the yearly temperature range near the poles is very large.
Low and High Latitudes
Atmospheric Circulation
• Cold air _____ because it is _____ than warm air. As the air sinks, it ______ and _______.
• Warm air _____. It expands and cools as it rises.
• Warm air can hold _____ water vapor than cold air can. Therefore, when warm air cools, the water vapor it contains may condense into liquid water to form rain, snow, or fog.
Atmospheric Circulation
• _____ energy heats the ground, which warms the air above it. This warm air rises, and cooler air moves in to replace it. This _______ of air within the atmosphere is called _____.
Atmospheric Circulation
Atmospheric Circulation
• Because the Earth ______, and because different latitudes receive different amounts of solar energy, a ______ of global atmospheric circulation results.
• This circulation pattern _______ Earth’s __________ patterns.
Global Circulation Patterns
• Cool air normally sinks, but cool air over the equator ______ ______ because hot air is rising up below it. This cool air is ______ _____ from the equator toward the North and South Poles where it __________ at about 30º north latitude and 30º south latitude.
Global Circulation Patterns
• Some of the air _____ back to the Earth’s surface and becomes warmer as it descends. This warm, dry air then moves across the _______ and causes water to _________ from the land below, _____ ___ _______.
Global Circulation Patterns
• At about __º north and __º south latitudes, this air ______ with cold air traveling from the poles.
Prevailing Winds
• Winds that blow ________ in one direction throughout the year are called _________ _____.
Prevailing Winds
• Because of the rotation of the Earth, these winds __ ___ blow directly northward or southward.
• Instead, they are _______ to the ____ in the _______ Hemisphere and to the ___ in the ________ Hemisphere.
Prevailing Winds
• Belts of prevailing winds are produced in both hemispheres between 30º north and south latitude and the equator.
• These belts of winds are called the _____ _____.
• The trade winds blow from the _______ in the Northern Hemisphere and from the __________ in the Southern Hemisphere.
Prevailing Winds• Prevailing winds known as the _______
are produced between 30º and 60º north latitude and 30º and 60º south latitude.
• In the Northern Hemisphere, these are southwest winds, and in the Southern Hemisphere, these winds are northwest winds.
• The _____ _______ blow from the poles to 60º north and south latitude.
Oceanic Circulation
• Ocean currents have a great effect on climate because water holds ____ _____ of ____.
Oceanic Circulation
• The _______ of ______ ocean _______ is caused mostly by ______ and the rotation of the Earth.
• These surface currents _________ warm and cool masses of water around the world and in doing so, they affect the climate in many parts of the world.
El Niño–Southern Oscillation
• ___ _____ is the warm phase of the El Niño–Southern Oscillation.
• It is the _____ occurrence in the _____ ______ Ocean in which the surface-water temperature becomes _______ ____.
El Niño–Southern Oscillation
• During El Niño, winds in the western Pacific Ocean (which are usually weak) strengthen and push warm water eastward.
El Niño–Southern Oscillation
• ______ follows this warm water eastward and produces _______ _______ in the _________ half on the ____, but _____ in ________ and ________.
El Niño–Southern Oscillation
• ___ _____ is the _____ phase of the El Niño–Southern oscillation. It is the periodic occurrence in the eastern Pacific Ocean in which the surface water temperature becomes unusually ____.
Pacific Decadal Oscillation
• The ______ _______ _______ ___ is a ____-_____, 20 to 30 year _____ in the ________ of warm and cold water masses in the Pacific Ocean.
• PDO _______ the climate in the northern Pacific Ocean and North America.
• It affects ocean surface temperatures, air temperatures, and precipitation patterns.
Topography
• Height above sea level (______) has an important effect on climate. Temperatures fall by about __°C (about 11°F) for every 1,000 m increase in elevation.
• Mountain ranges also influence the distribution of precipitation. This effect is known as a ____ _____.
• Both the ___ and ______ ______ influence Earth’s climate.
• At a solar _______, the sun emits an increased amount of ultraviolet (UV) radiation. UV radiation produces more _____, which ______ the stratosphere.
Other Influences on Earth’s Climate
• In large-scale volcanic eruptions, ______ _______ gas can reach the upper atmosphere, where it can remain for up to __ years.
• The sulfur dioxide, reacts with smaller amounts of water vapor and dust in the ___________, forming a bright layer of haze.
Other Influences on Earth’s Climate
• This layer of haze ______ enough sunlight to cause the global temperature to _______.
Other Influences on Earth’s Climate
Seasonal Changes in Climate
• The _______ result from the ____ of the Earth’s ___, which is about 23.5° relative to the plane of its orbit.
Seasonal Changes in Climate
• Because of this tilt the angle at which the sun’s rays strike the Earth changes as the Earth moves around the sun.
Seasonal Changes in Climate
• During _____ in the Northern Hemisphere, the Earth tilts _____ the sun and receives direct sunlight. Therefore, the amount of time available for the sun to heat the Earth becomes greater.
• During summer in the Northern Hemisphere, the _______ Hemisphere tilts ____ from the sun and receives less direct sunlight.
Seasonal Changes in Climate
• During the summer in the Southern Hemisphere, the situation is reversed.
• Example: Christmas in Australia and Panama = a sunny day at the beach.
End of section 1
Review q’s: 1,2,6,7,10,11,19,
20,26 and 27