Temperature Distribution: Factors and Impact

Temperature distribution across the Earth’s surface is influenced by various factors such as latitude, altitude, proximity to the sea, and atmospheric circulation. Understanding these factors helps us grasp why certain regions are hotter or colder than others, impacting climates and ecosystems.

Temperature Distribution and Anomalies

Temperature

• Definition: Temperature is the measurement in degrees of how hot (or cold) a thing (or a place) is.
• Isotherms: These are lines connecting places with equal temperatures. Isotherms shift with the apparent movement of the sun across the equator.
  • In the Northern Hemisphere, isotherms are irregular and closely spaced.
  • In the Southern Hemisphere, they are more regular and widely spaced. 
  • Isotherms, meant to align with latitudes on a uniform Earth, bend due to land-water heat differences. 
  • The general rule is that isotherms crossing from land to sea bend towards the pole (In winter) / equator (In summer).
• Temperature Anomaly: It indicates a place’s temperature differing from its latitude’s mean, with positive anomaly (e.g., Sahara Desert, temp > mean) and negative anomaly (e.g., Mt. Everest, temp < mean).

Factors Controlling Temperature Distribution

• Latitude: It has direct control on temperature as the insolation is inversely proportional to the latitude.
  • As locations move away from the Equator, the angle of sunlight decreases, spreading solar radiation over a larger area. 
  • This results in less intense heating and lower temperatures. 
  • The reduced angle of sunlight means the rays have to travel through more atmosphere, leading to greater absorption or reflection of heat and less reaching the Earth’s surface.
• Altitude(Elevation): The higher the altitude, the lower is the temperature. 
  • Altitude refers to the height above sea level, and as altitude increases, temperature decreases. 
  • For every 1,000 meters of increase in altitude, temperature drops by approximately 6.5 degrees Celsius. 
  • This cooling effect occurs because the air at higher altitudes is thinner, with lower concentrations of gases, dust, and water vapour compared to denser air at sea level. 
  • Consequently, thinner air is less effective at trapping heat, resulting in lower temperatures in areas at higher altitudes.

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• Albedo effect reduces temperatures (Decreasing Order of the Albedo: Fresh Snow (0.80) > Ocean ice > Sand > Green gross > Soil > Forest > Open ocean (0.06) > Charcoal (0.04))
• Distance from the Sea: The places situated near the sea come under the moderating influence of the sea and land breezes. Land heats and cools faster than the sea 
  • In Summer: In summer, the land heats quickly while the sea remains cooler, resulting in onshore winds bringing relief to coastal regions. 
  • In Winter: the sea retains warmth, and onshore winds bring milder temperatures to the coast. 
  • Continental Effect: This maritime effect leads to milder summers and winters along the coast. Inland areas, unaffected by the sea, experience greater temperature extremes, with hotter summers and colder winters, known as the continental effect.
• Air-mass Circulation and Ocean Currents 
  • Ocean currents influence wind temperatures, moderating coastal temperatures.
  • Warm Air Masses/Ocean Currents: higher temperature. 
  • Cold Air Masses/Cold Currents: low temperature.
• Prevailing Winds: Wind origin and speed affect temperature distribution.
  • Winds over warm ocean currents transport tropical water to the poles and warm coastal regions and increase rainfall.
  • Winds passing over cold ocean currents, originating from the poles, cool coastal areas, and reducing rainfall.
• Aspect of Slope (Relief): Aspect refers to a mountain’s position relative to the sun’s rays. The orientation of slopes influences sunlight exposure, affecting the temperature.
  • South-facing Slopes: in the Northern Hemisphere are warmer due to receiving more direct sunlight and being shielded from polar winds. 
  • North-facing Slopes: in the Southern Hemisphere are warmer for similar reasons. This is because they receive direct sunlight and are sheltered from polar winds, leading to a more concentrated distribution of heat.
• Day-Night Cycle: Rotation-induced temperature variations.
  • In June: the length of daylight increases from the equator to the poles in the Northern Hemisphere but decreases in the Southern Hemisphere. 
  • In December: Daylight decreases from the equator to the poles in the Northern Hemisphere and also decreases in the Southern Hemisphere. 
  • Summer and Winter: More daylight hours in summer lead to higher temperatures, while fewer daylight hours in winter result in lower temperatures, causing seasonal changes.
• Urban Heat Island (UHI) Effect: Human activities elevate temperatures in urban areas.

Conclusion

A multitude of factors, including latitude, altitude, proximity to the sea, and atmospheric circulation, play crucial roles in determining temperature distribution. By considering these factors, we can better understand the variations in temperature across different regions, aiding in weather prediction, climate modeling, and environmental management efforts.

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