Tuesday, August 14, 2007

Clear Skies for Farmers

Clouds form over native vegetation, but not farmland?

An article in today's Science Times alerts us to a situation where clouds regularly form on the native side of Austrailia's rabbit proof fence, but not on the side with farmland. These pictures, if truly representative, are striking!

The satellite view at right is of the southwestern corner of the island continent, near Perth. The beige ground, as in the air surveillance photo above, is cropland; the green is outback scrub. (From the information in the images, I presume the vantage from the plane is looking south.)

According to the article, the reasons for this phenomenon are not definite, but I'd put my money on the effects of dark vegetation absorbing heat in the day and 'releasing' it at night when it can combine with moisture in the lower atmosphere. The clouds shown in the photos are low level cumulus beneath higher cirrus clouds. Cumulus clouds often progress into cumulus congestus, and these can bring rain showers or thunderstorms if conditions favor growth into the fearsome cumulonimbus.

This could have considerable impact on the study of how agriculture impacts precipitation patterns.

Want to learn more about clouds? I recommend the Cloudspotter's Guide, published by the Cloud Appreciation Society.

1 comment:

Steve said...

Tom, this is reminiscent of a conversation I had with my father-in-law one time regarding the first mall (and more importantly, the subsequent large expanse of parking lot) to be built in mid-MO. He recalled that this made a difference to weather patterns, and similarly, from my time there, I noticed storms seemed reluctant to cross I-70. Unscientific on my part, and maybe I was seeing what I want to see, but this was certainly on a much smaller scale than mass farming. P.S. It was 109 yesterday, and 105 today in MO.