[AZ-Observing] Re: NWS Article: Urban Heat Island Effect on Monsoon Storms

Pretty much the same conclusions re: the so-called "heat island" were 
discussed by valley weatherman Ed Phillips, when he spoke to SAC some 
years ago, as I recall.
The other "issue" often discussed is the supposed loss of irrigated 
farmland to urban landscape... As I recall Phillips' discussion, this is 
about an equal trade-off, cropland vs. urban grass and landscape 
watering.  He showed a slide with the "worst pollution day" recorded, 
with only the top of the famous radio antenna on the Westward Ho in 
downtown Phoenix showing above a bank of smog... The photo was taken 
back in the 1940s...(!!!)
I recall seeing an aerial photo (in a  photo booklet by Kodak) taken 
over the west end of Camelback Mountain sometime in the 1950s.... All 
citrus groves, no houses then. Of course, its all subdivisions for many 
years, but the trees are still there, being watered by SRP 
irrigation...  (The last citrus stand on Camelback Rd. close up some 
years ago...)
Gene Lucas
(17250)

tpolakis@xxxxxxx wrote:

>This is sort of on-topic for Arizona observers, who often claim that the
>presence of Phoenix affects the number and intensity of summer storms...
>The Phoenix National Weather Service office Web site has a good summary of the 
>local and surrounding effects of the heat island on the monsoon:
>
>http://www=2Ewrh=2Enoaa=2Egov/psr/general/monsoon/MonsoonPMA=2Ephp
>
>And here is my summary version:
>
>- The heat island was first described in 1921, when the metropolitan area
>bustled with 80,000 residents
>
>- Everybody knows that the Phoenix nighttime lows have increased (by 7F to 13F 
>since 1961), but the same dataset shows the daytime highs decreasing by 0F to 
>4F.  They attribute it to the moderating effect of unnatural vegetation. The 
>"surrounding rural area" weather station that was used for comparison to 
>Phoenix is in the town of Maricopa, which has been doing its best to create 
>its own heat island in the past few years...
>
>- The contour maps of Valley rainfall do not support any of the anecdotal
>claims of "hot spots" for monsoon storms.  It simply increases with
>elevation with a good correlation.
>
>- And now the punch line: a plot of precipitation in Phoenix over 112 years 
>shows no upward or downward trend in precipitation as the population has 
>increased.
>Tom
>  
>

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