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