Deep Space is very cold - 272 o C Earth is much warmer than that! So where does the heat come from? The Sun!
Effect of Distance from the Sun Mercury Mean daytime temperature +350 o C Pluto Mean daytime temperature -230 o C 40 times as far from sun as Earth 1/3 as far from sun as Earth
Does Earth’s distance from the sun vary? yes, the orbit varies from circular to elliptical an elliptical orbit means that the sun is closer at some seasons than at others this is referred to as eccentricity
Is the earth tilted on its axis?Yes! Evidence? the seasons the Northern Hemisphere gets more solar energy in the summer and hence it is warmer then
Is this tilt constant?No! the tilt varies from 22.0 o to 24.5 o ! this change in tilt affect the energy arriving at different parts of the Earth
Does the location on a sphere affect how much solar radiation arrives at that place? Yes! The closer to the Equator, the more days the sun is directly overhead,
The same amount of light energy comes from the sun But that energy is distributed over a larger area as we move away from the Equator The result is that polar areas are cooler than Equatorial areas
Moon temperatures Day +110 o C Night -150 o C Does the atmosphere affect climate? How can we tell? Earth temperatures Day + 24 o C Night + 16 o C Well, the Earth and the Moon get the same amount of energy from the Sun and yet…
So clearly the atmosphere has two effects 1. It keeps the earth cooler during the day 2. It keeps the earth warmer at night How does it keep the earth cooler in the day? The atmosphere acts as an umbrella to keep some of the sun’s rays from reaching the Earth
How does it keep the earth warmer at night? The atmosphere acts like a blanket to keep heat in.
Does the atmosphere affect other aspects of climate? Winds!What makes winds blow? warm Warm, less dense air is pushed up Air now cools away from warm ground Cool, more dense air falls Sun’s rays warm the ground Surface winds move energy around the planet
How else do winds affect climate? Winds push ocean currents that also move energy around the Earth
Volcanoes and climate Volcanic ash rises high into the atmosphere as it is hot It blocks the sunlight from reaching the Earth and so causes cooling of the climate It may also act as a nucleus for cloud formation and increase rainfall
Places #1, #2 and #3 are all at the same latitude. Yet they do not experience the same climate? Why? 1 3 2
The atmosphere affects climate, what about the hydrosphere? Hydrosphere and climate McGraw Hill pg 343 8- D Comparing heat Absorption of Water and Soil