Due to the warming of the troposphere from the increased greenhouse effect of the polar stratospheric clouds, the stratosphere would cool and would potentially increase the amount of polar stratospheric clouds.
22.
The difference is said to have something to do with the action of polar stratospheric clouds at the South Pole that increase in winter and exacerbate the destruction of ozone in the Antarctic.
23.
During the spring, however, the sun comes out, providing energy to drive photochemical reactions and melt the polar stratospheric clouds, releasing considerable ClO, which drives the hole mechanism.
24.
Scientists have not been able to directly analyze the composition of polar stratospheric clouds previously, though some earlier aircraft flights provided indirect evidence that nitric acid and water were present, Mauersberger said.
25.
During the Antarctic winter and spring, however, reactions on the surface of the polar stratospheric cloud particles convert these " reservoir " compounds into reactive free radicals ( Cl and ClO ).
26.
Because of this, she said, this past winter should in fact have seen colder than normal temperatures over the Arctic, leading in turn to larger and longer-lasting polar stratospheric clouds.
27.
The polar stratospheric clouds, nine to 15 miles ( 15 to 24 kilometers ) above the Earth's surface, provide a place where chemical reactions occur in which chlorine attacks and destroys ozone.
28.
Using an array of satellites, weather balloons and high-flying aircraft, the scientists found that polar stratospheric clouds made of ice particles and nitric acid were larger and lasted longer than researchers had found in previous years.
29.
Since water vapor is the only supporting substance used in Type II polar stratospheric clouds, the presence of water vapor in the lower stratosphere is necessary where in most situations the presence of water vapor in the lower stratosphere is rare.
30.
Polar stratospheric clouds show little variation in structure and are limited to a single very high range of altitude of about, so they are not classified into �tages, genus types, species, or varieties in the manner of tropospheric clouds.
