082_Kasodariya_Lab2

LAB 2 – SUN-EARTH RELATIONSHIP LAB Student Name: Dhruv Kasodariya Tutorial Section: 082 Student Number: 3156993 PURPOSE The sun is our most important energy source, fueling nearly all life on earth. In this lab you will be learning about our annual journey around the sun. By the end of this lab, you should understand where the sun is in reference to the earth at various points throughout the year. You will learn to visualize the earth’s position relative to the sun, from the perspective of the whole earth, as well as from a single point on the globe. Finally, from the perspective of an observer on earth, you will learn to track the sun’s path through the sky, again at various points throughout the year, able to pinpoint the location of the sun in the sky in a given place at a given time. PART 1: UNDERSTANDING SUN-EARTH RELATIONSHIPS 1. Refer to what you learned in the lab lecture to fill in the following table . You might also refer to Figures 1 and 2 , or the helpful interactive digital models available at: https://www.earthspacelab.com . 8 Marks *Hint: Tangent is defined as “barely touching” the circle of illumination – the edge of the circle of illumination. *Hint: The Subsolar Point is the location where the Sun’s rays are striking perfectly perpendicular (at 90°) to Earth’s surface. Approx. dates for solstices and equinoxes March 20 th June 21 st September 22 nd December 21 st Common name for each date Spring equinox Summer solstice Fall equinox Winter solstice Latitude of the subsolar point 0 23.5 N 0 23.5 N Latitude of the tangent point ( N. Hemisphere) 90 N 66.5 N 90 N 66.5N 1 University of Winnipeg GEOG-1205L

Latitude of the tangent point (S. Hemisphere) 90 S 66.5 S 90 S 66.5 S 2. Complete the following table by calculating the Noon Sun Angle (i.e., altitude of the Sun) for the given locations and dates. 9 marks * Remember: A = 90° - L° +/- D° Where A = angle, L° = Latitude, and D° = Declination *Also remember that the declination is positive (+) if the location and the subsolar point are in the same hemisphere, it is negative (-) if they are in opposite hemispheres. Location Latitude Winter (December) Solstice Equinoxes Summer (June) Solstice Eureka, NU (80°N) -13.5 10 33.5 Churchill, MB (59°N) 7.5 31 54.5 Kharkiv, UKRAINE (50°N) 16.5 40 63.5 Kyoto, JAPAN (35°N) 31.5 55 78.5 Alice Springs, AUSTRALIA (23.5°S) 43 66.5 90 Kinshasa, DR Congo (4°S) 62.5 86 70.5 3. For the South Pole during the Winter (December) Solstice, complete the calculations below . 3 marks. a. Noon Sun Angle: ______23.5______ b. 0600 h (6:00 am) Sun Angle: ______23.5________ c. 1500 h (3:00 pm) Sun Angle: _____23.5________ 2 University of Winnipeg GEOG-1205L

*Note: for (b) and (c) the equation A = 90° - L° +/- D° cannot be used. *Hint: Think about the Earth’s rotation and tilt for this time of year. Or see the models at: https://www.earthspacelab.com to help with visualization. 4. A simple equation was used to calculate the Noon Sun Angle ; however, the same equation cannot be used for other times during the day. If we wish to calculate the altitude of the Sun at any other time, we could use the following equation. Where: ● a = the altitude of the Sun o the angle (°) above the horizon ● = the latitude of the location ● = the declination of the Sun o same as the latitude of the subsolar point ● h = the hour angle o h = 0° for noon and changes by 15° each hour from noon . o h = 15° at 11:00 and 13:00, h = 30° for 10:00 and 14:00, etc. a. Calculate the Altitude of the Sun for Winnipeg, MB (50°N) for the dates and times listed below: 8 marks . i. June 22 nd at 14:00 _____54.68 ° ________ ii. March 21 st at 07:00 ______9.58 ° _________ iii. December 22 nd at 16:00 _____-0.61 ° __________ iv. February 23 rd at 9:00 _____18.34 ° __________ *Hint: Working with the expression, the sine value for the sun angle will be calculated. To complete the calculation and derive the angle (a), you must take the inverse sin (sin -1 ) of this value. *Other Hint: Table 1 may be useful for a.iv. 5. A Sunpath Diagram may be used to determine both the Altitude of the Sun and the Azimuth of the Sun (i.e., the compass direction of the Sun in the sky). Figure 3 shows a Sunpath Diagram for 50°N (which can be used for Winnipeg). Table 1 lists declinations for selected dates. Using the Sunpath Diagram provided ( Figure 3 ), and the list of declinations ( Table 1 ) fill in the blanks below. 8 marks . a. August 12 th at 1000 h: Altitude of the Sun: ______48_____ Azimuth of the Sun: ________135°SE______ 3 University of Winnipeg GEOG-1205L

b. January 21 st at 1600 h: Altitude of the Sun: _______2______ Azimuth of the Sun: _____233°SW_________ c. September 23 rd Time of Sunrise: _____06:00 AM________ Azimuth of the Sun: _____0°E_______ d. June 22 nd Time of Sunrise: _____04:00 AM________ Azimuth of the Sun: ____52°E________ 6. Jay wants to put a solar panel on his new house in Winnipeg. a. If Jay wanted to capture the maximum amount of solar energy throughout the year with a fixed (non-moving) panel, what would the ideal direction and angle be? Explain why. 3 marks . It would be best for Jay to face his solar panel south because of the sun’s direction at an angle of 39 ° since it is the average of 63(highest point) and 15 (lowest point). b. If Jay wanted to capture the maximum amount of solar energy on the Summer (June) Solstice, with a sun-tracking (moving) panel… 14 marks . i. How many degrees would the panel need to rotate (0° - 360°) each hour , and in total from sunrise to sunset ? Each hour =____16.25____ Total From Sunrise to Sunset =_____260_____ ii. How many degrees would the panel need to tilt (0° – 90°) each hour , and in total from sunrise to sunset ? Each hour =___8___ Total From Sunrise to Sunset =___128_____ 4 University of Winnipeg GEOG-1205L