Understanding Earth’s Seasons

Key Points

• Causes of Seasons: Not due to proximity to the Sun, but rather:
  • Differences in the intensity of solar radiation.
  • Differences in the duration of daylight.

Misconception About Earth's Proximity

• Common Misbelief: Closer to the Sun in summer, farther in winter.
• Truth: Earth is closest to the Sun in January and farthest in July.
  • Northern Hemisphere: Close in winter, far in summer.

Explanation of Seasons

• Solar Radiation Angle:
  • High Sun angle = Concentrated radiation.
  • Low Sun angle = Diffused radiation.
• Tilt of Earth: 23.5-degree tilt affects how sunlight hits the Earth.

Importance of Earth's Tilt

• Summer Solstice (June 21):
  • Northern Hemisphere tilted toward the Sun.
  • Higher sun angle and more daylight.
  • Longest day of the year in Northern Hemisphere.
• Winter Solstice (December 21):
  • Northern Hemisphere tilted away from the Sun.
  • Lower sun angle and less daylight.
  • Shortest day of the year in Northern Hemisphere.

Daylight Variation

• Polar Extremes:
  • North of the Arctic Circle: 24 hours of sunlight in summer, darkness in winter.
  • Below Antarctic Circle: Reverse conditions.
• Near Equator:
  • Consistent sunlight and minimal day length variation.

Temperature Distribution

• Effect of Sun's Position:
  • Warmer temperatures near the equator due to direct sunlight.
  • Colder near poles due to less direct sunlight.

Energy Imbalance

• Heat Transfer Mechanisms:
  • Atmosphere and ocean circulation (winds and currents) help distribute heat.
  • Prevents extreme temperature changes over time.

Next Steps

• Upcoming Topic: Learn about atmospheric circulation patterns and the direction of global winds.