American Samizdat

Monday, October 23, 2006. *
The Ozone Monitoring Instrument on Nasa's Aura satellite measures the total amount of ozone from the ground to the upper atmosphere over the entire Antarctic continent.

In addition, scientists from US National Oceanic and Atmospheric Administration's (Noaa) Earth System Research Laboratory in Boulder, Colorado, used balloon-borne instruments to measure ozone directly over the South Pole.

By 9 October, the total column ozone had plunged to 93 Dobson Units (DU) from approximately 300 DU in mid-July. Dobson Units are a measure of ozone amounts above a fixed point in the atmosphere.

More importantly, nearly all of the ozone in the layer between eight and 13 miles above the Earth's surface had been destroyed. In this critical layer, the instrument measured a record low of only 1.2 DU, having rapidly plunged from an average non-hole reading of 125 DU in July and August.

"These numbers mean the ozone is virtually gone in this layer of the atmosphere," said David Hofmann, from the Noaa's Earth System Research Laboratory.

"The depleted layer has an unusual vertical extent this year, so it appears that the 2006 ozone hole will go down as a record-setter."
posted by thistle at 10:41 AM
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