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hours of daylight


vampares
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In the winter months the number of hours of day light are fewer than during summer months.

 

Below is a graph of the difference in daylight hours between Philadelphia, PA at ~39.5 north and Dallas, Texas ~32.6 north over the period of one year.

 

Philadelphia gets more daylight hours in the summer.

 

timediff_phl_dallas.png

 

The total daylight hours

 

Screenshot_4.jpg

 

The equator is interesting. The sun may change angle but the equator gets 12:07 hours of daylight every day of the year.

 

On the equinox every location on earth gets 12 hours of sunlight. This is March 20 and September 23.

Edited by vampares
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The equator is interesting. The sun may change angle but the equator gets 12:07 hours of daylight every day of the year.

 

On the equinox every location on earth gets 12 hours of sunlight.

Only one of those statements could be be correct.

 

I suspect they are both wrong (obviously, it's always sunny somewhere on the equator so it gets 24 hrs of sunlight a day. Any point on the equator must get pretty close to 12 hours a day )

Edited by John Cuthber
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On the Discovery channel there was this guy in the rain forests of Belize which is just under the horn of Mexico. 17 degrees north. Maximum daylight at best is 13:08. Guy was distraught.

Solstice occurs June 24. Daylight between June 1st and July 11 have the least amount of change from day to day.

 

 

Only one of those statements could be be correct.

I suspect they are both wrong (obviously, it's always sunny somewhere on the equator so it gets 24 hrs of sunlight a day. Any point on the equator must get pretty close to 12 hours a day )

On the equinox every location on earth gets 12 hours and 7 minutes of sunlight.

 

 

At the equator it is March 20th every single day of the year. While during the month of June I will experience 15 hours of sunlight the equator will still get only 12. By August 9th it is less than 14 hours per day.

 

London is a great city in the summer. The solstice gets 16:33 hours. They still get almost 15 hours on August 9th. Winter months are all dark. And only gets 7:55 at Christmas.

Edited by vampares
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Yep

 

The angle of radiation is important.

 

Take a unit circle. Radius of 1. The sunny half of circle, the longitude is 3.14 length. Diameter is 2. So the incoming area of radiation is 2 spread over 3.14.

 

On march 20th:

 

cos 0 =1 at the equator one. cos of 45 = 0.707 (or %70 grade direct sunlight at noon)

 

Dallas cos 35 = .819

Philadelphia cos 39 = .777

London cos 51= .63

 

Tropic of cancer and capricorn are at 23.5 degrees. London cos (51-23.5) = .89.

 

In theory London England will receive more radiation on the solstice than all other locations. That calculation was only high noon however. Look at the pole angle facing the sun it does present itself as a positive angle. Its not just living in the shadows.

 

Of course everything always averages out. The nature of circular trigonometry is not exactly kind at 51 degrees only receiving 63% for 12 hours on March 20. Whereby the "growing season" is shorter.

 

Screenshot_8.png

Edited by vampares
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:huh: There are zero hours of sunlight in the trash can, where this waste-of-time thread belongs at any time of year. Seriously; there is no defensible point to be made or discussion to be had here.

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According to the wundergrond solar panel energy calculator, Dallas Texas does receive more total daily solar energy on 6 months than does the equator.

There is a monthly variation of solar energy at the equator. But it always 12:07 sunlight per day.

This calculator may go by monthly averages which would not be 100% correct.

The solar energy at equator calculates 332 kWhr/year (I'm using the first panel)

Dallas texas 314 kWhr/year.

Philadelphia calculates 340 kWhr/year!

London however only gets 204 kWhr/year. :mad:

Edited by vampares
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Solar angle in essence dictates the solar energy. It is only directly over head at noon. Otherwise there is a reduction of energy.

On August ninth, the solar angle is higher in Dallas than Philadelphia after 7 o'clock in the morning.

June 10th is interesting a 5 o'clock am London is at 8.6 degrees


So what is the question?

Why are you so cold?

According to that wunderground solar energy calculator, 37 degrees gets 345 kWhr/year.

 

I've tried to find the calculations that were being preformed but I could not. It is all in JS which I don't know.

 

At 40 degrees gets 290 kWhr/year. 50 kWhr drop off which then eases off.

 

58 degrees still sees a month with nearly total the energy as the equator, of course this would be over the course of the extended day. 178 kWhr/year is a respectable number. Such a situation would be highly sensitive to any variation due to the low level of light at any one given point in time.


The high points of the 36-39 area are not due to the variations in the winter. These locations would experience the greatest effects of any climate change. Theoretically this region could become substantially hotter than the Sahara desert.

Edited by vampares
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Since I don't live in a state or province and don't have a zip code, that calculator isn't much use to me.

 

I have been using the latitude field on all of the sites. If you are in England you're probably 49.5. North maybe 51 or 52?

 

Seriously, Vampares, what use do you think this thread is?

Visibility. I want to be visible and I want people who I do not know to stare at me.

I would dominate a reality type show.

If you are looking for the underlining cynicism, I have not formed my thoughts about daylight saving time yet.

Screenshot_8.png

How do spell yamika?

Edited by vampares
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