Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 18/07/2012 05:30:01

Title: Why aren't the solstices in the middle of the season?
Post by: thedoc on 18/07/2012 05:30:01
Daniel Fienberg  asked the Naked Scientists:
   
Hi Chris,

I wanted ask why the summer solstice (or the solstice for any season for that matter) is not in the middle of the season. I know that season might be defined arbitrarily and the solstice is not, so I guess what I am asking is why the solstice is not in the middle of the hottest three month period of the year but rather toward the beginning of that three month period.

Looking forward to hearing from you,

Daniel Fienberg

What do you think?
Title: Re: Why aren't the solstices in the middle of the season?
Post by: syhprum on 18/07/2012 06:03:58
I think it depends on which part of the word you live in the UK most years our winter does not start until the end of December or our summer until the end of June.
Title: Re: Why aren't the solstices in the middle of the season?
Post by: Geezer on 18/07/2012 06:57:12
As Syhprum says, it depends where you are.

In the UK winter is timed so that the solstice falls in the middle of winter. In the US, winter only starts on the solstice. The delay in the US does seem to align quite well with the typical weather conditions here - probably something to do with the large land mass. Also, the US is much further South (New York is around the same latitude as Madrid) so the change in the amount of daylight is not as noticeable as it is in the UK.

Title: Re: Why aren't the solstices in the middle of the season?
Post by: CliffordK on 18/07/2012 08:32:54
If you put an ice cube tray in your freezer.
Then set the freezer to oscillate between -20°C and +30°C.
Say your solstices are when the freezer hits -20°C and +30°C, and your equinoxes are at +5°C.

You would find that the maximum ice extent would not be at the coldest setting of the freezer, but the time when the temperature hits the minimum, then returns to 0°C.

In fact, you might not have any ice formation until the freezer dips significantly below 0°C as your tray of warm water is being cooled.  Some Ice would certainly persist past the +5°C equinox.  Perhaps all the way until the temperature reaches the maximum temperature.

So, if  you based your seasons on the ice extent in this hypothetical freezer, you would find the seasons shifted somewhat.  Likewise, temperatures of the water/ice would also be somewhat shifted from the real heating/cooling energy curve.

Obviously real weather patterns are complex, and, one sees temperature gradients from the poles to the equator.  However, the idea of heating & cooling the surface of the Earth and the lower atmosphere like a giant heat sink would be similar.
Title: Re: Why aren't the solstices in the middle of the season?
Post by: simplified on 18/07/2012 08:59:44
Yes ,the maximal quantity of thermal energy collects to time of downturn of the sun.
Title: Re: Why aren't the solstices in the middle of the season?
Post by: syhprum on 18/07/2012 09:26:12
I am pleased to note that our misplaced gulf stream to due to move back North where it belongs but I expect a wet drive to Mannheim tomorrow.
Title: Re: Why aren't the solstices in the middle of the season?
Post by: Geezer on 18/07/2012 20:50:36

I expect a wet drive to Mannheim tomorrow.


Watch out for swerving steamrollers.