Re: The Seasons

In article <odysseus1479-at-5E933F.14312907042007@xxxxxxxxxxxxxx>,
Odysseus <odysseus1479-at@xxxxxxxxxxxxx> wrote:

In article <ev7kmc$2923$1@xxxxxxxxxxxxxx>,
pausch@xxxxxxx (Paul Schlyter) wrote:

In article <JJuRh.35908$_c5.17623@attbi_s22>,
Sam Wormley <swormley1@xxxxxxxxx> wrote:

What causes seasons?
http://curious.astro.cornell.edu/question.php?number=196

[...] If you were standing on the tropic of cancer on June 21,
the sun would be directly overhead at noon. This is the first day of
summer in the northern hemisphere, and the first day of winter in the
southern hemisphere.

That's the first day of *astronomical* summer/winter. There are
meteorological definitions of the seasons too. Since they depend on
the weather, the dates of the start of the meteorological seasons
vary with both place and year.

And then there are the traditional definitions (from China and
northwestern Europe, at least), which place the seasonal epochs at or
near the "cross-quarters", when the Sun's longitude is 90n + 45 degrees,
halfway between the solstices and the equinoxes. For example the holiday
now known as Hallowe'en or All Saint's Day once marked the beginning of
winter.

The four seasons spring-summer-autumn-winter only work for temperate
latitudes btw. At tropical latitudes it's pointless to talk about
"winter" because they never have any winter. It's also pointless to
talk about "summer", because they always have summer. Theis seasons
are the "rain time" and "dry time". Near the equator they have "rain
time" twice a year, near the equinoxes. And near the tropics they
have "rain time" once a year, near the summer solstice. There isn't
much rain in e.g. Sahara ever of course, but the little rain they get,
they do get near their summer solstice.

And southern Asia, with land towards north and ocean towards south, has a
very special climate, with its monsoons....

The arctic regions also have its own set of seasons. Some people there
consider the year having no less than eight (!) seasons..... all different
from our four seasons....


Btw, when does astronomical summer start right at the equator? At the
June solstice, or at the December solstice? <g>

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