Contact: Stephanie Kenitzer FOR IMMEDIATE RELEASE
301-713-0622 4/28/95
Average ozone measurements over regions of the Northern Hemisphere for January-March 1995 were significantly lower (311 Dobson Units) than those recorded during the same months last year (333 DUs). However, this year's values are not lower than record-setting measurements observed during 1993 (302 DUs). Dobson Units are the standard way to express total column ozone amounts in the atmosphere.
These and other findings were released this month in the National Oceanic and Atmospheric Administration's (NOAA) Northern Hemisphere Winter Summary, now available on the Internet on the Climate Analysis Center's World Wide Web Home Page, at http://nic.fb4.noaa.gov.
The report also indicates that satellite-based Northern Hemisphere ozone measurements during 1994-1995 winter months were 10 to 20 percent lower than those observed during the same months in 1979 and the early 1980s. These findings are for latitudes approximately 30 degrees north of the equator extending to the North Pole. The 1979 and early 1980s values for the region 30N-50N were 332 DUs compared to 311 DUs observed this past winter.
"While it is too early for us to draw any firm conclusions about the low ozone values this year, we are noticing continued low values of ozone compared to 15 years ago," said Alvin J. Miller, branch chief, Climate Diagnostic Branch, Climate Analysis Center. "NOAA will continue monitoring and reporting the ozone values over both the Northern Hemisphere and the Antarctic in an effort to determine causes and trends."
The ozone layer shields the Earth from harmful ultraviolet radiation from the sun. Natural events such as volcanoes, solar flares and man-made gases can produce changes in ozone concentration.
NOAA's Climate Analysis Center issues ozone summary reports in April and December.