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Sun Path

Kalamazoo, MI

Coordinates: Latitude 42.28 & Longitude -85.55 (ZIP Code Centroid)

Time Zone: Eastern (Standard Time: GMT -5 hours, DST: GMT -4 hours).

To start the SunPath Module, created at Australian National University, open Internet Explorer. From the menu options, select File>Open, and use the Browse button to locate the giscart.lab(s:/) server. The module can be found in the geog105/solar/Sun/Sun.html folder on the server.

Give the module a moment to open. Go to the Sun Path module first (on the left).

At the bottom of the Sun Path page is an animated java applet of sun movements. If the applet does not show up immediately, be patient. If it still doesn’t appear, double-click the coffee-mug symbol in the lower right corner of the computer screen, near the time.

Take a moment and experiment with the applet, and see how sun position changes given the different variables.

• Enter the latitude for your Kalamazoo, select yearly simulation type, and begin the simulation on January 15.

• Run the yearly simulation by clicking on the forward play button, watching the box in the lower right for the progression of time shown in the simulation.

In your own words describe how the sun's position at noon changes over the course of a year in Kalamazoo.

 

When is your birthday? ___________ What is today’s date? _____________

Use the simulator to compare the sun’s position for today’s date and your birthday. How does the position of the sun differ between the two dates?

• Run the annual simulation again as above, but change the time to 4:00pm, beginning on January 15.

How does the sun’s position at 4:00pm change with respect to the horizon an annual basis in Kalamazoo?

 

For the same Kalamazoo location, fill in the table below for sun-rise and sunset times, the length of day between sunrise and sunset, and the altitude at noon (sun angle above horizon).  If you need help calculating the length of day here is a length of day calculator. Hint: Use the forward play to scan through for sunrise times and the backward play to scan back for sunset times or use the step play buttons.

|15th of Month |sunrise |sunset  |length of day  |Altitude Deg|

| |(hr:min) |(hr:min) |(hr:min) | |

|Jan |  |  |  |  |

|Feb |  |  |  |  |

|Mar |  |  |  |  |

|Apr |  |  |  |  |

|May |  |  |  |  |

|Jun |  |  |  |  |

|Jul |  |  |  |  |

|Aug |  |  |  |  |

|Sep |  |  |  |  |

|Oct |  |  |  |  |

|Nov |  |  |  |  |

|Dec |  |  |  |  |

Graph the length of day and altitude on the attached graphing page.

In the Northern hemisphere the shortest day of the year is near December 21(winter solstice) and the longest day is near June 21 (summer solstice).

What is the length of day at Kalamazoo for Dec 21?               Does the length of day vary much between Dec 15 and Jan 15?

What is the length of day at Kalamazoo for June 21?               Does the length of day vary much between Jun 15 and Jul 15?

 Between what two months does the length of day increase most rapidly?

 Between what two months does the length of day decrease most rapidly?

 When is the sun highest sky?

When is the sun lowest in the sky?

Now use an atlas to determine the latitude of your Spring Break dream vacation spot.

Where would you choose to go? _______________ What is the latitude of that location? _____________________

Check the sun’s position for noon at the your Spring Break location in comparison to Kalamazoo for next Friday, February 25, the first day of our Spring Break. How does the altitude differ? Why?

How does the daylength for next Friday differ between the two locations?

Where do you have the best possibility for getting a good sun tan? Describe in terms of both sun altitude and daylength.

Photovoltaic Power

Similar relationships hold true for solar power. Photovoltaic panels produce increased energy with increased altitude, daylength and low cloud cover. Open the photovoltaic module, which is similar to the sun path module from the main web page at the beginning of the assignment.

Change the location to USA, Detroit, MI. What is the total energy that can be captured annually at Detroit?

Click the Graph res. button to graph the data. Does the energy curve for Detroit look how you would expect? Why or why not?

Similarily, check how much energy could be captured with the same photovoltaic setup in USA, Tuscon, AZ. How does the Tuscon, AZ graph differ from the Detroit graph? What variables could you use to explain this difference?

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