2. Duration and Intensity of Solar Radiation

3. Sunlight June 21/22 - Summer Solstice in Northern Hemisphere Sunlight is directly over Tropic of Cancer. The length of time the Tropic of Cancer is exposed to daylight on this date is greater than the length of time it is in darkness. (The yellow line is longer than the red line.) This means more solar radiation is received and temperatures are higher. This is the duration of solar radiation received.

4. June 21/22 - Winter Solstice in Southern Hemisphere Sunlight The opposite is true at the Tropic of Capricorn. The length of time the Tropic of Capricorn spends in the daylight is shorter than in darkness. Therefore, less solar energy is received here, and temperatures are cooler. It is winter in the Southern Hemisphere.

5. Notice that above the Arctic Circle, 66.5 o N, the sunlight is constant. The sun never sets. It is called the “Land of the Midnight Sun”. South of the Antarctic Circle the opposite is true: 24 hours of no (direct) sunlight.

7. Here the angle of incidence of the sunlight is directly overhead, or at 90 0 to the horizon. The sun’s energy is the most intense.

9. Here at the Tropic of Capricorn the angle of incidence of the sunlight is directly overhead, or at 90 0 to the horizon. The sun’s energy is the most intense. This is the summer solstice. Here at the Tropic of Cancer the angle of incidence of the sunlight is much less direct and therefore less intense. This is the winter solstice.