© 2007, John Wiley and Sons, Inc. Physical Geography by Alan Arbogast Chapter 9 Global Climates Lawrence McGlinn Department of Geography State University of New York - New Paltz

© 2007, John Wiley and Sons, Inc. Weather vs. Climate Weather – state of the atmosphere at a specific place and time on Earth’s surface. Climate – average values of weather elements, such as temp and precipitation, over an extended period of time “Climate is what you expect, weather is what you get.” –Mark Twain

© 2007, John Wiley and Sons, Inc. Variables that Influence Climate Latitude – intensity of radiation, length of day Seasonality – annual variation of sun angle Air Circulation – predictable – weather systems Maritime/Continental – proximity to water can increase precip. and reduce temp range Topography – local topography can impact climate, e.g. windward vs. leeward side of mts.

© 2007, John Wiley and Sons, Inc. Köppen Climate Classification System Describes world climates based on: Avg monthly temp Avg monthly precip Total annual precip 6 major climate groups based on latitude: A-E & H Further subdivided by temp and precip.

© 2007, John Wiley and Sons, Inc. Primary Letter – based on latitude Exceptions: B and H climate types Secondary letter – based on seasonal changes in precipitation Tertiary letter – based on seasonal changes in temperature Exceptions: A and E climate types have no tertiary letter Köppen Climate Classification System

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Tropical Climates (A) Average temp of every month > 18ºC Mesothermal Climates (C) Coldest month average temperature - 3ºC At least 1 month average temperature > 10ºC Microthermal Climates (D) Average temperature of warmest month >10ºC Average temperature of coldest month < -3ºC Primary Letters

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Polar Climates (E) Average temperature of all months < 10ºC Dry Arid and Semiarid Climates (B) Evaporation > precipitation Highland (H) Primary Letters

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Secondary Letters These letters are based primarily on seasonal precipitation: f = adequate rainfall all through the year, no distinct dry season w = winter dry (keep in mind the hemisphere), if 70% or more of annual rainfall occurs in summer s = summer dry, if 70% or more of annual rainfall occurs in winter m = extremely wet summer = monsoon. A climate only.

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Secondary Letters For B climate only: S = semiarid = steppe W = arid = desert which results in either BS or BW. For E climate only: T = tundra F = perpetual frost = permanent ice which results in either ET or EF.

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Tertiary Letters The third letters in the system are based exclusively on seasonal and annual temperature : a = hot summer, warmest month > 22°C; C and D only b = warm summer, warmest month < 22°C; C and D only c = cool summer, < 4 months over 10°C; C and D only d = very cold winter, coldest month < -38°C; D only h = dry-hot, annual temperature > 18°C; B only k = dry-cold, annual temperature < 18°C; B only

© 2007, John Wiley and Sons, Inc. Köppen’s Climate Classifications Examples of Combinations Af = Tropical Rainforest climate type Am = Tropical Monsoon climate type BWh = Low-Latitude Hot Desert climate type Cfa = Humid Subtropical climate type Csa = Mediterranean climate type Dfb = Humid Continental climate type ET = Tundra climate type

© 2007, John Wiley and Sons, Inc. Global Distribution of Climates

© 2007, John Wiley and Sons, Inc. Tropical Climates (A) Straddle Equator from 25º N to 25º S Avg. Monthly temp. exceeds 18ºC (64ºF) Subdivided by precipitation: Af – tropical rainforest – wettest Am – tropical monsoon Aw – tropical savanna - drier

© 2007, John Wiley and Sons, Inc. Tropical

AfAf

Ecuador Tropical Rainforest - Af Northern Australia Tropical Savanna - Aw

© 2007, John Wiley and Sons, Inc. Arid/Semi-Arid Climates (B) Poleward of A climates on all continents Subsiding air from STHs - Moister on fringes Subdivided by temp & moisture: BWh – 15-30º N & S – hot - little precip BWk - <15 cm precip/yr – high temp range BSh – more temp range & precip than BWh BSk – rainshadow – convectional precip – high temp range

© 2007, John Wiley and Sons, Inc. Arid and Semiarid Climates (B)

© 2007, John Wiley and Sons, Inc. BWh

© 2007, John Wiley and Sons, Inc. BWk

© 2007, John Wiley and Sons, Inc. BSh

© 2007, John Wiley and Sons, Inc. BSk

© 2007, John Wiley and Sons, Inc. Jordan – Hot, Low-latitude Desert - BWh Northcentral China – Cold, mid latitude Desert - BWk Eastern Colorado, USA Cold, mid latitude Steppe - BSk California, USA - Hot, low latitude Steppe - BSh

© 2007, John Wiley and Sons, Inc.

Physical Geography by Alan Arbogast Chapter 9 con’t Global Climates Lawrence McGlinn Department of Geography State University of New York - New Paltz

© 2007, John Wiley and Sons, Inc. Mesothermal Climates (C) 20º- 60º N & S – where most people live A warm and a cool season Cfa, Cwa – hot, humid summer – east side of continents – 20-35º N & S Csa, Csb – west coast of continents – near 35º N & S – winter wet season, dry summer Cfb, Cfc – west coast of continents – 35-60º N & S – mP air & orographic processes

© 2007, John Wiley and Sons, Inc. Mesothermal Climates (C) Mesothermal Climates (C)

© 2007, John Wiley and Sons, Inc. Cfa

© 2007, John Wiley and Sons, Inc. Csa

© 2007, John Wiley and Sons, Inc. Southern California – Mediterranean Dry-Summer Climate - Csa Western Washington – Marine West-Coast Climate - Cfc

© 2007, John Wiley and Sons, Inc. Microthermal Climates (D) Poleward of C climates, 35º- 60º N & S Long winters, limited summer warmth Dfa, Dwa – large annual temp range – jet stream & cyclonic precip, most in summer Dfb, Dwb – very large annual temp range – mild summer, harsh, dry winter Dfc, Dwc, Dwd – long, bitter winters - short, cool summers – little precip – highest annual temp range on Earth

© 2007, John Wiley and Sons, Inc. Microthermal Climates (D)

© 2007, John Wiley and Sons, Inc. Dfa

© 2007, John Wiley and Sons, Inc. Dwa

© 2007, John Wiley and Sons, Inc. Eastern US – Humid Continental Hot-Summer Climate - Dfa Northern Michigan – Humid Continental Mild-Summer Climate - Dfb Central Canada - Subarctic Climate – Dfc

© 2007, John Wiley and Sons, Inc. Polar Climates (E) Latitudes >70º N & S Long, cold winters w/little precip. 2 Subcategories: ET – temp moderated by ocean – precip mostly June-Oct.- polar high dominates EF – interior Greenland and Antarctica – always brutally cold – polar desert

© 2007, John Wiley and Sons, Inc. Polar and Highland Climates

© 2007, John Wiley and Sons, Inc. ET

© 2007, John Wiley and Sons, Inc. EF

© 2007, John Wiley and Sons, Inc. Highland Climates (H) Associated with large mtn ranges, e.g. Andes, Rockies, Alps, etc. Cooler/colder than surrounding lowlands, even in tropical or equatorial regions Often wetter than surroundings due to orographic precip.