Chapter 10

Chapter 10: Midlatitude, Polar, and Highland Climate Regions

Mesothermal Climates (C)

  • Midlatitude, mild winters.

  • Influenced by:

    • Polar front

    • Westerlies

    • Trade winds

  • Weather changes are caused by migrating cyclones and anticyclones.

Locations with Mesothermal Climates

  • Examples:

    • San Francisco, CA

    • Bluefield, WV

    • Columbia, SC

    • Chengdu, China

    • Sevilla, Spain

    • Nagasaki, Japan

    • Dunedin, New Zealand

  • Climate types include:

    • Humid subtropical

    • Marine west coast

    • Mediterranean

Humid Subtropical Climate

  • Classification: Cfa (hot-summer) or Cwa (winter-dry).

  • Characteristics:

    • Dominated by moist maritime tropical air (mT).

    • Two varieties exist:

    • Hot-summer (Cfa):

      • Most rainfall is convective and occurs in the summer.

      • Additional winter precipitation via cP air mass invasions.

    • Winter-dry (Cwa):

      • Prevails in Asia, influenced by monsoon winds, resulting in rainfall during summer and dry conditions in winter.

Precipitation Data and Climographs

  • Columbia, South Carolina:

    • Population: 116,000

    • Latitude/Longitude: 34°N, 81°W

    • Average Annual Temperature: 17.3°C (63.1°F)

    • Total Annual Precipitation: 126.5 cm (49.8 in.)

    • Elevation: 96 m (315 ft)

    • Annual Temperature Range: 20.7°C (37.3°F)

    • Annual Hours of Sunshine: 2800 hours

  • Summary Statistics:

    • Precipitation: ranges shown for different months and gauges.

    • Temperature: ranges from warmer months through winter.

Humid Subtropical - Hot Summer Classification

  • Characterized by warm temperatures and significant summer rainfall.

Humid Subtropical Winter-Dry (Cwa)

  • Example: Chengdu, China

    • Latitude/Longitude: 30°40'N, 104°04'E

    • Average Annual Temperature: 17°C (62.6°F)

    • Total Annual Precipitation: 114.6 cm (45.1 in.)

    • Elevation: 498 m (1633.9 ft)

    • Population: 2,500,000

    • Annual Temperature Range: 20°C (36°F)

    • Annual Hours of Sunshine: 1058 hours

  • General climatic patterns illustrating monsoonal effects on precipitation throughout the year.

Marine West-Coast Climate (Cfb, Cfc)

  • Characteristics:

    • Situated on midlatitude west coasts.

    • Moist mP air masses causing cyclonic storms.

    • where mountains exist, orographic lifting leads to high precipitation.

  • Example: Dunedin, New Zealand

    • Latitude/Longitude: 45°54'S 170°31'E

    • Average Annual Temperature: 10.2°C (50.3°F)

    • Total Annual Precipitation: 78.7 cm (31.0 in.)

    • Elevation: 1.5 m (5 ft)

    • Population: 120,000

    • Annual Temperature Range: 14.2°C (25.5°F)

General Soil and Environment Conditions

  • In marine west-coast regions, lowland soils may lose nutrients due to high precipitation levels.

  • Fertilizers are needed for successful cultivation.

  • Typical vegetation includes dense needle-leaf forests, with broadleaf deciduous forests prevalent in Europe.

Mediterranean Dry-Summer Climate (Csa, Csb)

  • Climate characteristics:

    • Winter: wet and mild

    • Summer: very dry

  • Location: typically along western coastlines of continents.

  • Seasonal air mass dynamics:

    • Subtropical high shifts poleward in summer, blocking marine air intrusions.

Mediterranean Climograph - Example Monterey, California

  • Latitude: 36°N

  • Characteristics:

    • Notable weak annual temperature cycle

    • Very dry summer conditions

    • Mild and humid winters

  • Precipitation details, temperature ranges across the year.

Agricultural Resources in the Mediterranean Environment

  • Dominates with crops and greenhouse agriculture.

  • Cultivation typically includes cereals (wheat, barley, oats) and a variety of fruits (citrus, olives, grapes, nuts).

  • Major irrigation practices in lowland areas for crop growth are seen.

Microthermal Climates (D)

  • Regions characterized by cold winters, prevalent in mid- and high-latitudes.

  • Observed strong seasonal temperature ranges and increased seasonality.

Types of Microthermal Climates

  • Humid Continental Climate:

    • Hot summers (Dfa, Dwa) and mild summers (Dfb, Dwb).

    • Located in central and eastern areas of North America and Eurasia.

    • Largest seasonal temperature variations.

    • Greatest precipitation during summer season when maritime air masses invade, contrasted by cold winters dominated by continental polar and Arctic air influences.

Examples of Humid Continental Climates

  • New York, NY:

    • Avg. Annual Temperature: 13°C (55.4°F)

    • Total Annual Precipitation: 112.3 cm (44.2 in.)

    • High annual temperature oscillation.

Agricultural Resources of Humid Continental Climate

  • Significant potential for crop diversity due to rich, fertile soils during the moist summer growing season.

  • Notable crops: corn, wheat, rye, oats, barley, beet sugar, soybeans, and rice.

Subarctic Climates (D)

  • Include severe winter conditions with short summer periods.

  • Show significant temperature ranges, especially evident in Siberia.

Polar and Highland Climates

  • Types include tundra climate, ice cap and ice sheet climates, and highland climates.

  • Overall, tundra climates are seen along arctic coastal regions with cold air mass influences, while highland climates have moisture-laden orographic rain patterns.