Temperature distribution on Earth is a complex interplay of factors. Insolation, the Earth's tilt, and orbit create seasonal variations. Latitude, altitude, and land-sea distribution shape global temperature patterns, while atmospheric and oceanic circulation redistribute heat across the planet.

Surface characteristics and land use also play crucial roles in local temperature variations. Albedo, vegetation cover, and soil moisture affect energy balance. Urban heat islands, deforestation, and agricultural practices can significantly impact regional temperatures, highlighting the intricate relationship between human activities and climate.

Temperature Distribution on Earth

Insolation and Seasonal Variations

• Insolation, or incoming solar radiation, is the main source of energy that drives temperature variations on Earth
  • The amount of insolation received at a given location is determined by factors such as:
    1. Angle of the sun
    2. Length of the day
    3. Atmospheric conditions (cloud cover, aerosols, greenhouse gases)
• The Earth's axial tilt and its orbit around the sun create seasonal variations in temperature
  • Changes in the angle and duration of insolation received at different latitudes throughout the year lead to seasonal temperature patterns
  • Examples of seasonal temperature variations:
    • Higher temperatures during summer in the Northern Hemisphere when the North Pole is tilted towards the sun
    • Lower temperatures during winter in the Southern Hemisphere when the South Pole is tilted away from the sun

Primary Factors Influencing Temperature Distribution

• The primary factors that influence temperature distribution on Earth's surface are:
  1. Latitude
  2. Altitude
  3. Land-sea distribution
  4. Atmospheric and oceanic circulation patterns
  5. Surface characteristics
• These factors interact with incoming solar radiation to create the observed patterns of temperature across the globe
  • Examples of temperature distribution patterns:
    • Higher average temperatures near the equator compared to the poles
    • Temperature variations between coastal and inland locations at the same latitude

Latitude, Altitude, and Land-Sea Influence

Latitude and Solar Angle

• Latitude affects temperature distribution because the angle at which the sun's rays strike the Earth's surface varies with distance from the equator
  • Lower latitudes (closer to the equator) receive more direct sunlight and have higher average temperatures
  • Higher latitudes (closer to the poles) receive more oblique sunlight and have lower average temperatures
• The solar angle determines the intensity and duration of insolation received at a given location
  • A higher solar angle (sun directly overhead) results in more concentrated insolation and higher temperatures
  • A lower solar angle (sun closer to the horizon) results in more dispersed insolation and lower temperatures

Altitude and Adiabatic Lapse Rate

• Altitude influences temperature patterns, with temperatures generally decreasing as elevation increases
  • This is due to the adiabatic lapse rate, which is the rate at which air temperature changes with altitude
  • The average environmental lapse rate is approximately 6.5°C per 1,000 meters of elevation gain
• Factors contributing to the adiabatic lapse rate include:
  1. Decreasing atmospheric pressure with altitude
  2. Expansion and cooling of rising air parcels
  3. Reduced absorption of infrared radiation by the thinner atmosphere at higher altitudes
• Examples of temperature variations with altitude:
  • Lower temperatures at the summit of Mount Everest compared to sea level
  • Cooler temperatures in high-altitude cities like La Paz, Bolivia, compared to coastal cities at the same latitude

Land-Sea Distribution and Heat Capacity

• Land-sea distribution affects temperature patterns because land and water have different heat capacities and rates of heating and cooling
  • Land surfaces heat up and cool down more quickly than water bodies, resulting in larger temperature variations over land compared to oceans
  • Coastal regions tend to have more moderate temperatures due to the influence of nearby water bodies
  • Interior regions experience greater temperature extremes due to their distance from the moderating effects of oceans
• The specific heat capacity of water is higher than that of land
  • Water requires more energy to change its temperature compared to an equal volume of land
  • This results in slower temperature changes in water bodies and more stable temperatures in coastal areas
• Examples of land-sea temperature differences:
  • The maritime climate of San Francisco, California, with moderate temperatures influenced by the nearby Pacific Ocean
  • The continental climate of Omaha, Nebraska, with more extreme temperature variations due to its inland location

Atmospheric and Oceanic Circulation Impact

Atmospheric Circulation Patterns

• Atmospheric circulation, driven by the uneven heating of the Earth's surface and the Coriolis effect, plays a significant role in distributing heat and moisture around the planet
• The major atmospheric circulation patterns include:
  1. Hadley cell circulation near the equator
     • Brings warm, moist air from the equator towards the subtropics
     • Influences temperature patterns in tropical and subtropical regions
  2. Ferrel cell circulation in the mid-latitudes
     • Characterized by the movement of air from the subtropics towards the poles
     • Affects temperature distribution in temperate regions
  3. Polar cell circulation in high latitudes
     • Involves cold, dry air descending at the poles and moving towards the mid-latitudes
     • Contributes to the formation of polar climates
• Jet streams, which are fast-moving air currents in the upper atmosphere, can influence the movement of air masses and the distribution of heat and moisture
  • The polar jet stream, located between the Ferrel and Polar cells, can affect the movement of cold air masses from the poles towards the mid-latitudes
  • The subtropical jet stream, located between the Hadley and Ferrel cells, can influence the movement of warm, moist air from the tropics towards higher latitudes

Oceanic Circulation and Heat Distribution

• Oceanic circulation, such as surface currents and deep ocean circulation, redistributes heat from the equator towards the poles, affecting global temperature patterns
• Warm ocean currents, like the Gulf Stream, transport heat from the tropics to higher latitudes
  • The Gulf Stream moderates temperatures in western Europe, resulting in milder winters compared to regions at similar latitudes in North America
  • Other examples of warm currents include the Kuroshio Current in the western Pacific and the Agulhas Current in the Indian Ocean
• Cold ocean currents, such as the California Current, bring cooler water from higher latitudes towards the equator
  • The California Current contributes to the relatively cool coastal temperatures along the western coast of North America
  • Other examples of cold currents include the Canary Current in the eastern Atlantic and the Humboldt Current off the coast of South America
• The coupled atmosphere-ocean system, through processes like the El Niño-Southern Oscillation (ENSO), can cause significant temperature anomalies and impact global climate patterns
  • During El Niño events, warmer-than-average sea surface temperatures in the eastern Pacific can lead to changes in atmospheric circulation and global temperature patterns
  • La Niña events, characterized by cooler-than-average sea surface temperatures in the eastern Pacific, can also influence global temperature distribution

Surface Characteristics and Land Use Influence

Surface Characteristics and Energy Balance

• Surface characteristics, such as albedo, vegetation cover, and soil moisture, can influence local temperature variations by affecting the amount of solar radiation absorbed or reflected by the surface
• Albedo refers to the proportion of incoming solar radiation that is reflected by a surface
  • Surfaces with high albedo, like snow and ice, reflect more radiation and contribute to cooler temperatures
  • Surfaces with low albedo, like dark soil or vegetation, absorb more radiation and lead to higher temperatures
  • Examples of albedo effects on temperature:
    • The high albedo of the Greenland Ice Sheet contributes to lower surface temperatures
    • The low albedo of the Amazon Rainforest leads to higher absorption of solar radiation and warmer temperatures
• Vegetation cover can impact local temperatures through processes like evapotranspiration
  • Evapotranspiration releases moisture into the atmosphere and has a cooling effect on the surrounding area
  • Regions with dense vegetation cover, such as tropical rainforests, tend to have more moderate temperatures compared to areas with sparse vegetation
• Soil moisture content affects the partitioning of energy between sensible and latent heat fluxes
  • Moist soils can contribute to cooler temperatures through increased evaporation and latent heat flux
  • Dry soils can lead to higher temperatures due to reduced evaporative cooling and increased sensible heat flux

Land Use Changes and Temperature Variations

• Land use and land cover changes, such as urbanization, deforestation, and agricultural practices, can modify local temperature patterns
• Urban areas often experience the urban heat island effect, where temperatures are higher compared to surrounding rural areas
  • Factors contributing to the urban heat island effect include:
    1. Reduced vegetation and increased impervious surfaces
    2. Increased surface absorption of solar radiation by dark materials (asphalt, concrete)
    3. Anthropogenic heat sources (vehicles, industrial processes, air conditioning)
  • Examples of urban heat islands:
    • Higher temperatures in the center of Tokyo compared to its surrounding suburbs
    • Warmer nighttime temperatures in New York City compared to nearby rural areas
• Deforestation can lead to local temperature increases by reducing evapotranspiration and altering surface albedo
  • Removal of forest cover reduces the cooling effect of evapotranspiration and exposes the underlying soil, which may have a lower albedo
  • Deforestation in the Amazon Rainforest has been linked to local temperature increases and changes in regional climate patterns
• Agricultural practices, such as irrigation and the creation of bare soil surfaces, can influence local temperature patterns
  • Irrigation can lead to cooler temperatures through increased evaporation and latent heat flux
  • Bare soil surfaces, such as those created by tillage or fallow periods, can have higher albedo and contribute to local temperature variations
  • Examples of agricultural impacts on temperature:
    • Cooler temperatures in irrigated croplands compared to nearby non-irrigated areas
    • Temperature differences between fields with different crop types or growth stages due to variations in albedo and evapotranspiration