[Prev][Next][Index][Thread]

Re: (meteorobs) leonids

>I believe that the best place on the planet to
watch the 2002 Leonids will
>be in the American Southwest -- Arizona and New
Mexico. This is because the
>primary factor affecting observed rates is
weather. The probability of good
>clear weather in November in most of North
America -- except the Southwest
>-- is less than 50%. In the Southwest it's more
like 95%. The second factor
>is the altitude of the radiant at the time of the
peak. That favors the east
>coast.

My figures when analysing weather images from 1995
to 2001 supports
your impression. I looked at every weather picture
from Nov. 11
to Nov 22. in these years and estimated the
probability for seeing
the event at several sites. The figures indicate a
probability
of 81-83% for sites along the Mexican border.
The more you go to the North the lower the chances
are. Nevada, or Denver, have 60% probability, as
have sites
in the Midwest (e.g. Indiana). So high altitude
sites not
too far from the Mexican border seem to be best.

The following table gives the results (Clear sky
estimate in %, hr= radiant altitude at maximum in
degrees
hl=lunar altitude at maximum, twilight = beginning
of astr. twilight in UT, sun 18 deg below
horizon).
Expected maximum time is 10:29.

                 Clear skies %       hR  hl
twilight UT
Palomar            81                42  39
12:49
Kitt Peak          82
Puebla (Mexico)    85                55  23
11:26
Big Bend TX        83                54  28
11:54
Indiana            63                62  16
11:03
Denver             61                50  30
12:15
Nevada             57

Generally frontal systems cross the continent from
West to East, and the weather should be better the
more you go to
the south and the more you go to the east. There
are however
episodic invasions of clouds from the south,
especially
in El Nino years (eg 1997), and they are the
reason that sites
in Texas or even Mexico do not fare much better
than those
in southermost California. I don't know how much
fog can
affect weather in the east and Midwest. It appears
that
even in the east, the chances to see the event are
much
better than in central Europe. Note however that
the time
window shrinks dramatically from W to E.

Though going to the southwest appears to be a good
idea, one
still should search for internet access to be
alert, flexible and mobile
in case of clouds entering the region from the
south or southwest.

For a comparison: Last years Leonids, in a similar
analysis
gave around 60-70% for Australia, 80-85% for
Mongolia and NE
China, and 75% in Korea.


Hartwig








The archive and Web site for our list is at http://www.meteorobs.org
To stop getting all email from the 'meteorobs' lists, use our Webform:
http://www.meteorobs.org/subscribe.html