World ClimatesWorld Climates

Chapter 21, Section 2Chapter 21, Section 2

The KThe Köppen Climate Classification öppen Climate Classification SystemSystem

The Köppen climate classification system uses mean monthly and annual values of temperature and precipitation to classify climates

The Köppen system has five principle groups: humid tropical climates, dry climates, humid mid-latitude climates, polar climates, and highland climates

All of these, except dry climates, are defined by temperature

Dry climates are classified according to the amount of precipitation

Climates of the WorldClimates of the World

Concept CheckConcept Check

What is the Köppen climate classification system?

The Köppen system uses mean monthly and annual values of temperature and precipitation to classify climates.

Humid Tropical ClimatesHumid Tropical ClimatesHumid tropical climates are climates without

wintersEvery month in such a climate has a mean

temperature above 18ºCThe amount of precipitation can exceed 200

cm per yearWet Tropical Climate – high temperatures

and much annual precipitation (Rainforests)Tropical Wet and Dry Climate –

temperatures and precipitation similar to the wet tropics, but experience distinct periods of low precipitation (Savannas)

Rainforests vs. SavannasRainforests vs. Savannas

Concept CheckConcept Check

Describe the characteristics of humid tropical climates.

Humid tropical climates have no winters. Every month has a mean temperature above 18ºC and has a lot of precipitation.

Humid Mid-Latitude ClimatesHumid Mid-Latitude Climates

Climates with mild winters have an average temperature in the coldest month that is below 18ºC but above -3ºC

Climates with severe winters have an average temperature in the coldest month that is below -3ºC

Humid mid-latitude climates include: humid subtropical, marine west coast, dry-summer subtropical, humid continental, and subarctic

Humid Subtropical Climate – generally located on the eastern side of a continent and characterized by hot, sultry summers and cool winters

Marine West Coast Climate – found on the windward coasts from 40º and 65º latitude and dominated by maritime air masses; winters are mild, and summers are cool

Dry-Summer Subtropical Climate – located on the west sides of continents between 30º and 45º latitude; the only humid climate with a strong winter precipitation max

Subarctic Climate – found north of the humid continental climate and south of the polar climate; bitterly cold winters and short cool summers; highest annual temperature range

Humid Mid-Latitude with Mild Humid Mid-Latitude with Mild WintersWinters

Humid Mid-Latitude with Severe WintersHumid Mid-Latitude with Severe Winters

Concept CheckConcept Check

What type of climate does LA have? Explain.

LA has a dry-summer subtropical climate. It is on the west-side of the continent, located between 30º and 45º latitude, and experiences all of its precipitation in the winter.

Dry ClimatesDry Climates A dry climate is one in which the yearly precipitation is not as

great as the potential loss of water by evaporation Dryness is not only related to annual rainfall, but is also a

function of evaporation Evaporation is closely dependent upon temperature There are two types of dry climates: arid (desert) and semi-arid

(steppe) The steppe is a marginal more humid variant of the desert,

separating the desert from the humid climates Dry climates exist as the result of the global distribution of air

pressure and winds Other dry climates are a result of rain shadows off of large

mountain chains Some of Earth’s driest climates occur where a cold ocean

current affects the west coast of a continent

Extent of Dry Climate ZonesExtent of Dry Climate Zones

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What defines a dry climate?Both the amount of precipitation that falls

and the amount that can be lost as the result of evaporation.

Polar ClimatesPolar Climates

Polar climates are those in which the mean temperature of the warmest month is below 10ºC

Polar winters are periods of perpetual night, making temperatures extremely cold

In the summer, temperatures remain cool despite the long days

Very little precipitation falls in polar regions There are two types of polar climates: the tundra

climate (treeless region) and the ice cap climate (permanent ice and snow)

Two Types of Polar ClimatesTwo Types of Polar Climates

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What are the characteristics of polar climates?

Polar climates are extremely cold, even in the summer months. Very little precipitation falls in polar regions, and evaporation is limited.

Highland ClimatesHighland Climates

Highland climates are localizedThey are much different than their

surrounding climatesThe conditions vary abruptly from one

place to anotherSouth-facing slopes are warmer than

north-facing slopes In general, highland climates are cooler

and wetter than nearby areas at lower elevations

Concept CheckConcept Check

How do highland climates compare with nearby lowland climates?

Highland climates are usually cooler and wetter than nearby places at lower elevations.

AssignmentAssignment

Read Chapter 21, Section 2 (pg. 592-599)Read Chapter 21, Section 2 (pg. 592-599)Do Chapter 21 Assessment #1-32 (pg. 609-Do Chapter 21 Assessment #1-32 (pg. 609-

610)610)