At Australia’s Bunny Fence, Variable Cloudiness Prompts Climate Study

Tuesday, August 14th, 2007

At Australia’s Bunny Fence, Variable Cloudiness Prompts Climate Study:

The rabbit-proof fence — or bunny fence — in Western Australia was completed in 1907 and stretches about 2,000 miles. It acts as a boundary separating native vegetation from farmland. Within the fence area, scientists have observed a strange phenomenon: above the native vegetation, the sky is rich in rain-producing clouds. But the sky on the farmland side is clear.

Why?

One theory is that the dark native vegetation absorbs and releases more heat into the atmosphere than the light-colored crops. These native plants release heat that combines with water vapor from the lower atmosphere, resulting in cloud formation.

Another hypothesis is that the warmer air on the native scrubland rises, creating a vacuum in the lower atmosphere that is then filled by cooler air from cropland across the fence. As a result, clouds form on the scrubland side.

A third idea is that a high concentration of aerosols — particles suspended in the atmosphere — on the agricultural side results in small water droplets and a decrease in the probability of rainfall. On the native landscape, the concentration of aerosols is lower, translating into larger droplets and more rainfall.

(Hat tip to FuturePundit.)

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