Seasons and Factors

Understanding the Earth's Seasons

• The amount of energy from solar radiation that reaches the top of the Earth's atmosphere is constant.
• The distance between the poles and the equator is not significant enough to explain why the poles are colder.
• The poles are colder than the equator due to the diffused nature of the sunlight reaching them.
• Direct radiation refers to concentrated sunlight, while diffuse radiation refers to spread-out sunlight.
• The control of temperature on Earth is influenced by latitude, with cooler temperatures as we move further north.
• Net radiation is the difference between incoming and outgoing energy, with the equator having a surplus and the poles having a deficit.
• Seasonality refers to the shortening or lengthening of the day and the angle of the sun.
• The equator experiences little to no seasonality, while the poles have extreme seasonality with 24-hour darkness in winter and 24-hour daylight in summer.
• The location of the sub-solar point, where the sun's rays are perpendicular to the surface, determines the sun's declination.
• The tilt of the Earth's axis is the primary reason for the seasons, with summer occurring when the axis is tilted towards the sun and winter when it is tilted away.
• Rotation refers to the Earth spinning on its axis, taking 24 hours for one rotation.
• Revolution refers to the Earth's orbit around the sun, taking 365 and a quarter days.

Temperature Changes in the Atmosphere and the Role of Greenhouse Gases

• Greenhouse gases like carbon dioxide and methane are efficient at absorbing energy, particularly the energy re-radiated from the Earth.
• Without greenhouse gases, the surface temperature would be much colder.
• The concentration of carbon dioxide in the atmosphere has steadily increased over the years, with the current level being around 415 parts per million.
• Humans are responsible for the increase in carbon dioxide concentration through activities like burning fossil fuels.
• The increase in carbon dioxide concentration is a result of the industrial revolution and the use of fossil fuels.
• The carbon dioxide concentration fluctuates seasonally, with higher concentrations in the winter and lower concentrations in the summer.
• The temperature in the stratosphere increases due to the presence of ozone, which absorbs ultraviolet light and heats up as a result.
• Ozone in the stratosphere protects life on Earth by blocking harmful ultraviolet light.
• Ozone at the Earth's surface is a pollutant and can cause irritation to the lungs.
• The temperature in the mesosphere decreases as we move away from the surface of the Earth.
• The temperature in the thermosphere increases due to the absorption of energetic particles from the sun, despite the low density of particles in this region.
• There is a difference between temperature and heat, with temperature being the measure of how fast particles are vibrating and heat being the amount of energy present.