FreeLists / az-observing / [AZ-Observing] Re: Weather in AZ

["AJ Crayon" <acrayon@xxxxxxx>]

It seems Dick has motivated Tom to come up with some interesting data. 
Something I've come to enjoy.  While the numbers from Tom's analysis seem to 
indicate we have had better weather than what we believe, I think we are 
missing some part of the discussion.  That part has to do with nights when 
most of us are able to get out with our telescopes.  Normally this is one or 
two weekends per month and not the entire month.  It is this kind of weekend 
where the weather has an impact on our hobby.  Yet the data doesn't seem to 
reach this level of detail - does it?

Clear skies,
aj

----- Original Message ----- 
From: "Tom Polakis" <tpolakis@xxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Tuesday, January 29, 2008 9:07 AM
Subject: [AZ-Observing] Re: Weather in AZ


--- Richard Harshaw <rharshaw2@xxxxxxx> wrote:
> I'm not a big fan of the "man is causing global warming" scare-- I think 
> it
> is more likely due to solar activity and natural planetary cycles.  But 
> one
> does wonder if this may not be due to a global climate change?


I am a big fan of analyzing data, and drawing conclusions from it, as 
everybody on this list should be.  If I am not intimately involved in a 
particular discipline such as climatology, I trust the conclusions of the 
science community more than anybody.

The recent cloudiness in Arizona hasn't been any more than slightly below 
average.  Brian Skiff has been gathering cloudiness data for Flagstaff since 
1980 (http://www.lowell.edu/Research/cloudiness_data/clouds.html), and i 
have the yearly data plotted through 2006 here.

http://members.cox.net/tpolakis/astro/clouds1.jpg

You can see that there really was no "golden age" when it was always clear 
in Arizona.


Now look at this monthly plot of average with 1-sigma standard deviation.

http://members.cox.net/tpolakis/astro/clouds3.jpg


Typical number of "clear" nights for for Winter are:

December: 11 +/- 4
January: 10.5 +/- 4

What we have so far for 2007-08 (assuming cloudy nights through the rest of 
January) are:

December: 8
January: 7

So you could say that this Winter storm season has been worse than average 
for observing, but only slightly so.

Tom
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