Ozone Hole

NOAA/NCEP Release: 98-178
Antartic Ozone Depletion Sets New Size Record

NASA and NOAA satellites show that the Antarctic ozone thinning covers the largest expanse of territory since the depletion developed in the early 1980s. The measurements were obtained this year between mid-August and early October using the Total Ozone Mapping Spectrometer (TOMS) instrument aboard NASA's Earth Probe (TOMS-EP) satellite and the Solar Backscatter Ultraviolet Instrument (SBUV) aboard the NOAA-14 satellite. "This is the largest Antarctic ozone hole we've ever observed, and it's nearly the deepest," said Dr. Richard McPeters, Principal Investigator for Earth Probe TOMS.

Preliminary data from the satellites show that this year's ozone depletion reached a record size of 10.5 million square miles (27.3 million square kilometers) on Sept. 19, 1998. The previous record of 10.0 million square miles was set on Sept. 7, 1996. The ozone level fell to 90 Dobson units on Sept. 30, 1998. This nearly equals the lowest value ever recorded of 88 Dobson Units seen on Sept. 28, 1994, over Antarctica. Scientists are not concerned that the hole might be growing because they know it is a direct result of unusually cold stratospheric temperatures, though they do not know why it is colder this year. ...