GPH 314 Cerveny Climate Controls

Climate Controls Definition

  • Climate control refers to factors that influence the climate of a given area or space.

  • Changes in climate controls can lead to climate change.

Major Climate Controls

  1. Positioning of Continents

    • The geographical position of a continent over the poles influences climate.

    • When a continent is situated over a pole, it facilitates cold air pooling, leading to ice formation and potentially Ice Ages.

    • Example: During the Cretaceous period, there was no polar continent, resulting in much warmer global temperatures (6-14 degrees Fahrenheit warmer than today).

    • Over the last two million years, Antarctica has been located over the South Pole, allowing for ice age formation.

    • Critical Point: A polar continent is a prerequisite for any ice age, although its presence does not guarantee one.

  2. Topography

    • Local geographical features such as mountains significantly impact regional climates.

    • Example: In Phoenix, mountains block moisture flow from the ocean, resulting in much drier conditions compared to coastal areas like San Diego.

    • Cold temperatures in Antarctica are attributed to both high elevation (over 7000 feet above sea level) and extensive ice coverage.

  3. Continentality

    • Refers to the distance from oceans and the moderating effects of large water bodies on climate.

    • Water has a high heat capacity, which means it heats up and cools down more slowly compared to land.

    • Example: San Diego, being close to water, maintains milder temperatures due to the moderating influence of the ocean. In contrast, Phoenix experiences greater temperature variability due to its interior location.

    • Example: International Falls shows extreme temperature variations, ranging from -40°F in winter to nearly 100°F in summer, due to its distance from the ocean.

  4. Atmospheric Composition

    • The composition of atmospheric gases can vary and significantly impact climate.

    • Water Vapor: The only gas that varies significantly day-to-day; others remain relatively constant.

    • Sulfur Gas: Released during volcanic eruptions; reflects sunlight and can lead to cooler regional climates post-eruption. Acts like sunscreen, decreasing temperatures following eruptions lasting from years to decades.

    • Carbon Dioxide (CO2): A greenhouse gas that retains heat. Human activity has increased its levels, thickening the "heat-trapping blanket" around the earth, leading to predicted temperature increases of 3-5 degrees Fahrenheit by the century’s end.

  5. Ocean Currents

    • Ocean currents carry waters of varying temperatures that significantly affect climate.

    • Example: The Humboldt Current off South America is cold and contributes to the aridity of the coastal desert.

    • The Gulf Stream, a warm ocean current along the U.S. East Coast, makes Europe significantly warmer than it would otherwise be at the same latitude.

    • Ocean gyres: Circular ocean currents that connect different currents, impacting climate on a larger scale.

    • Example: The loop of water formed by the Humboldt Current returns cold water to Antarctica, influencing temperatures across regions.

  6. Latitudinal Position

    • Position on Earth affects the amount of solar radiation received, influencing climatic conditions.

    • The Intertropical Convergence Zone (ITCZ): A band of low pressure near the equator that shifts seasonally, causing rainfall variations—North in summer, South in winter.

    • At 30 degrees North and South, Sub-Tropical High Pressure zones lead to dry climates; this is where many of the world’s largest deserts are found (e.g., Sahara Desert and Australian Desert).

    • Polar Fronts: Areas around 60 degrees North and South characterized by migratory storms and winds leading to weather changes.

Wind Patterns

  • Westerlies: Dominant winds blowing from west to east between 30-60 degrees latitude in both hemispheres.

  • Trade Winds: Northeast Trade Winds and Southeast Trade Winds operate between the equator and 30 degrees latitude.

  • Rossby Waves: The flow of westerlies is disrupted by continents, resulting in wave-like patterns of atmospheric flow leading to weather changes (e.g., ridges and troughs).

Local Circulation Effects

  • Monsoonal Circulation: Strong seasonal wind patterns that bring dramatic changes in rainfall.

    • Winter in India: High pressure from cold air over the Himalayas creates dry conditions.

    • Summer in India: Heating leads to low pressure, allowing moist ocean air to flow in, causing intense monsoon rains.

  • Southwest U.S. experiences a weak monsoon because significant oceanic moisture sources are absent.

Interplay of Climate Controls

  • Climate is typically influenced by a combination of the above controls. Moreover, other factors such as the presence of ice, snow, and vegetation can further modify local climates.

Conclusion

  • These various factors contribute individually and collectively to influence climate, with implications that extend beyond Earth, potentially leading into the study of climates on alien worlds in advanced courses.