Climate Classification

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Climate Classification

• Review of Major Controls of Climate
• Climate Classification
• Classification Types
• Hypothetical Continent
• Köppen Climate Classification
• Chapter 7.4

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Major Controls of Climate
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• Latitude
• Atmospheric circulation
• ITCZ, STH, Polar Front, Polar Highs
• Oceanic circulation
• Warm versus cold currents
• Distribution of land and sea
• Maritime versus continentality
• Orography

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Climate Classification
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• An aim of climatology has been to develop a
  regional climatology of the Earth
• The objective is to develop succinct descriptions
  of climatic conditions likely to be encountered
  at any point on Earth

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Climate Classification
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• A climate classification scheme leads to the
  creation of a series of climate types
• Provided the scheme leads to a manageable number
  of these, they can be mapped to produce climate
  regions

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Classification Types
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• Climate Classification schemes can be divided
  into two types

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Classification Types
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• Genetic
• Emphasizes the role of the climate controls
  (atmospheric dynamics) in creating climate and
  its various regional expressions
• Relates to the origin of the features

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Classification Types
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• Empirical
• Aims to produce a quantitatively defined series
  of distinct regions without regard to the causes
  of the climate
• Relates to the observation of features

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Climate Classification
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• Most climate classification schemes are empirical
  in nature
• While an empirical classification can be based on
  any observed climate variable, temperature and
  precipitation are the most commonly used

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Climate Classification
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• Temperature
• Hot
• Warm
• Cool
• Cold
• Small or large continentality

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Climate Classification
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• Precipitation
• No dry season
• Short dry season
• Long dry season
• No wet season (arid)
• Summer dry or winter dry

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Climate Classification
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Cold/Tundra
No Dry Season
Continental
Temperate Summer Dry
Temperate Moist
Hot and Dry
Hot Long Dry Season
Hot Short Dry Season
Hot and Wet Hot and Wet
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Subtropical HighsCross Section across Continents
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Conditionally unstable,
Stable,
rising air
sinking air
H
East coast
Ocean
West coast
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Climate Classification
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• Many classifications have been proposed
• Thornthwaite
• Based on the surface water balance
  (precipitation, evaporation, and their seasonal
  variations)
• Köppen
• Based on temperature and precipitation
• Heavily influenced by vegetation thresholds

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Köppen Climate Classification
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• Based on observed temperature and precipitation
  measurements

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Köppen Climate Classification
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• Each climate region is categorized by a series or
  two or three letters
• The first letter initially separates dry from
  moist climates and then, for the latter, divides
  them on the basis of temperature

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Köppen Climate Classification
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• A second letter then defines the degree of
  aridity for the dry climate and the temporal
  distribution of precipitation for the moist ones
• A third letter is used to characterize the
  seasonal variations in temperature for mid- and
  high-latitude climates

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Köppen Climate Classification
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• A Tropical Climates
• Hot to warm all year
• Af Rainy all year
• Am Short to medium length dry period
  (monsoonal)
• Aw Long dry season

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Köppen Climate Classification
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• B Dry Climates
• Evaporation exceeds precipitation on average
  throughout the year
• BW arid climates
• BS semi-arid climates
• h warm/hot temperatures
• k cool temperatures

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Köppen Climate Classification
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• C Mesothermal Climates
• Warm summers and cool winters
• Cf moist all year
• Cs summer dry
• Cw winter dry
• a hot summer
• b warm summer
• c cool summer

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Köppen Climate Classification
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• D Microthermal Climates
• Warm summers and cold (severe) winters
• Df moist all year
• Ds summer dry
• Dw winter dry
• a hot summer
• b warm summer
• c cool summer

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Köppen Climate Classification
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• E Polar Climates
• These climates have no true summers
• ET no true summers
• EF Perennial ice

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Köppen Climate Classification
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• H Highland Climates
• Temperatures similar to E climates, but due to
  altitude
• Not a climate region originally defined by Köppen

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Köppen Climate Classification
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Figure 7.10
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Köppen Climate ClassificationSan Francisco and
Boulder
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• San Francisco Mediterranean Climate
• Csb Climate
• C mesothermal climate
• s dry summer
• b warm summer
• Boulder Mid-Latitude Steppe Climate
• BSk Climate
• B dry climate
• S semi-arid climate
• k cool temperatures

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