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Chapter 10: Middle-Latitude, Polar, and Highland Climate Regions
Physical Physical GeographyGeographyNinth EditionNinth Edition
Robert E. Gabler
James. F. Petersen
L. Michael Trapasso
Dorothy Sack
Middle-Latitude, Polar, and Highland Climate Regions
Forests surround a small glacier in Alaska
10.1 Middle-Latitude Climates
• Microthermal and Mesothermal: – A lot of change and most of
the World’s population!– Changing seasons
associated with:• Migrating air masses• Cyclonic activity along polar
front.
10.1 Middle-Latitude Climates
• Humid Mesothermal Climate Regions– Moderate temperate (mesos)– Seasonality (long summers and short winters)
10.1 Middle-Latitude Climates
• Mesothermal Climates
10.1 Middle-Latitude Climates
• Mediterranean (Csa, Csb)– Location: west coasts 30o-
40o latitude– Alternation of subtropical
High in summer (dry) and westerlies in winter (wet)
– Csb has lower summer temp. (strong maritime)
– Csa has hot summers (continentality)
10.1 Middle-Latitude Climates
• Mediterranean– Special Adaptations– Chaparral
Q: Why is it unusual to find redwoods growing in this climate?
10.1 Middle-Latitude Climates
• Humid Subtropical Climate (Cfa)– Location: east coasts 15o and
20o to 40o latitude– Warm, moist air circulates
from the south around subtropical High in summer (wet and hot)
– Westerlies in winter (wet and cool)
10.1 Middle-Latitude Climates
• Humid Subtropical Climate (Cfa)– Subject to Tropical Storms,
convectional activity, and/or monsoon
– Wetter than Mediterranean even though similar latitude.
10.1 Middle-Latitude Climates
• Humid Subtropical Climate (Cfa)– Productive Climate– Long growing season
10.1 Middle-Latitude Climates
• Marine West Coast (Cfb and Cfc)– Location: 40o and 65o
latitude.– Continuous influence of
westerlies– Ample precipitation
• Mild-summer (Cfb)• Cool-summer (cfc)
10.1 Middle-Latitude Climates
• Ocean Influences– Moderating influences on temperature– Ocean current may increase– Smaller diurnal and annual temperature range
Q: How do you explain these differences?
10.1 Middle-Latitude Climates
• Clouds and Precipitation– Very cloudy, foggy
(advection fog), rainy, and stormy (cyclonic storms)
– Mountains increase precip. on windward side
– Heavy snow
10.1 Middle-Latitude Climates
• Resource Potential– Advantages for
agriculture– Small annual temp
range, long growing season, and abundant precip. favor plant growth
– Root crops, deciduous fruits, berries, grapes, grass, and timber
10.2 Humid Microthermal Climate Regions
• Humid Microthermal (35o-75oN)– Variable– Four distinct seasons– Continentality
10.2 Humid Microthermal Climate Regions
• Humid Microthermal– Humid continental, hot summer (Dfa, Dwa)– Humid continental, mild summer (Dfb, Dwb)– Subarctic with a cool summer (Dfc, Dfd, Dwc,
Dwd)– Similarities:
• All of these experience surplus of precip over potential ET
• Year round precip. (except area in Asia)• High frequency of mT in summer and cP in winter• Cyclonic storms and polar jet
10.2 Humid Microthermal Climate Regions
• Humid Microthermal
10.2 Humid Microthermal Climate Regions
• What areas of the U.S. average the greatest number of days of snow cover?
10.2 Humid Microthermal Climate Regions
• Humid Continental, Hot Summer (Dfa, Dwa)– Large geographic distribution in North America,
much smaller in Europe and Asia– Greatest agriculture potential– Longer growing season– Lower fuel bills
• Internal Variations of Dfa, Dwa– Growing season (140-200 days) depends on lat.– Continentality– Large lakes– Temp and precip decrease poleward
10.2 Humid Microthermal Climate Regions
• Internal Variations of Dfa, Dwa– Precipitation decrease
away from sea water.
Q: Why does precipitation decrease inland and poleward?
10.2 Humid Microthermal Climate Regions
• Seasonal Changes– Winter (cold and snowy)– Spring (warmer with frequent showers)– Summer (Hot and humid with occasional violent
thunderstorms)– Fall (clear and rainy, mild days, and frosty
nights)
10.2 Humid Microthermal Climate Regions
10.2 Humid Microthermal Climate Regions
• Humid Continental, Mild Summer (Dfb, Dwb)– Lies adjacent to and poleward of Dfa and Dwa– More continental with severe winters– Highly variable weather– Many cyclonic storms along polar front
• Mild-Summer & Hot-Summer ComparisonQ: What characteristics of these climographs distinguish
them from Galesburg, IL. & Northeast China
10.2 Humid Microthermal Climate Regions
10.2 Humid Microthermal Climate Regions
• Mild-Summer & Hot-Summer Comparison– More severe winters– Shorter growing season– Less precipitation, but
more snowfall
10.2 Humid Microthermal Climate Regions
• Human Activity– Dairy farming, quick ripening
varieties, grazing, animals, or orchards
– Poorer soil due to glacial impact during Pleistocene
– Many recreational activities
10.2 Humid Microthermal Climate Regions
• Subarctic (Dfc, Dfd, Dwc, Dwd)– At least one month with an average temperature
above 10oC (50oF)– Farthest poleward of microthermal climates
10.2 Humid Microthermal Climate Regions
• Subarctic (Dfc, Dfd, Dwc, Dwd)– Found only in N. hem– Ocean Currents
• East Coast: subarctic is further south• West: subarctic is further north
– Subarctic covers vast areas of Eurasia and North America
10.2 Humid Microthermal Climate Regions
• Subarctic (Dfc, Dfd, Dwc, Dwd)– Short cool summers and long harsh winters
Q: Why would people settle in such severe-winter climate regions?
10.2 Humid Microthermal Climate Regions
• Limiting Environment– Plants and animals– Taiga (boreal forest)– Very short growing season
(50-75 days)
10.2 Humid Microthermal Climate Regions
• Limiting Environment– Permafrost: permanently
frozen ground– Permafrost varies greatly
in thickness and is often discontinuous
– Freeze/thaw cycle– Patterned ground (frost
polygons)– Little to no agriculture– Mining
10.3 Polar Climate Regions
• Polar Climates (furthest from equator)– No month averages above 10oC (50oF)– No summer– No trees– Large annual net loss of radiation– Two Climate types:
• ET (Tundra)• EF (ice sheet)
10.3 Polar Climate Regions
• Polar Climates (ET and EF)
• Tundra Climate (ET)– Extremely short, cool “summer”– Muskeg
10.3 Polar Climate Regions
• Tundra Climate (ET)Q: What is the preferred means of travel in the
summer?
10.3 Polar Climate Regions
• Ice-Sheet Climate (EF)– Covers large areas on Northern and Southern
hemispheres (Greenland and Antarctica)
10.3 Polar Climate Regions
• Ice-Sheet Climate (EF)– Coldest place on earth is Antarctica (minimum
insolation, high albedo, and high elevation)
10.3 Polar Climate Regions
• Human Activity in Polar Regions– Inuit– Oil (Alaska’s North
Slope)– Scientific interest
10.3 Polar Climate Regions
• Highland Climate– Temperature decreases
with increasing altitude– Exposure
• Coastal or interior location
• High or low latitude• Slope aspect
10.3 Polar Climate Regions
Q: Taking into consideration the location of the stations, during what season does the maximum precipitation on the windward slope occur?
10.3 Polar Climate Regions
• Peculiarities of Mountain Climates– Tree line– Snow line
Q: What do you see in the photo that indicates prevailing wind direction?
10.3 Polar Climate Regions
• Peculiarities of Mountain Climates– Tropical Mountain
regions
Q: When Europeans first settled in the highlands of tropical S. America, in which vertical climate zone did they prefer to live in?
10.3 Polar Climate Regions
• Highland Climates and Human Activity– High pastures– Timber– Minerals– Recreation– With warming, tropical
highlands may become new areas of settlement
10.3 Polar Climate Regions
Physical Geography
End of Chapter 10: Middle-Latitude, Polar, and Highland Climate Regions