Tracking
the "Ozone Hole"
Ozone, which derives from ordinary oxygen (O2),
is our enemy at ground level, where it is a principal component of
human smog and at sufficient concentrations can be toxic to people,
animals and plants. At the level of the stratosphere, however, it is
our friend, forming an atmospheric layer some 12 to 20 miles up that,
even at concentrations of a few parts per million, absorbs with extraordinary
efficiency ultraviolet (UV) radiation from the sun that has been shown
to weaken human immune systems, to cause skin cancer in animals and
to affect the biochemistry and physiology of plants. Thus the discovery
in 1985 by a British Antarctic expedition of a "hole" in
the earth's protective ozone layer over that continent was regarded
as a major world environmental crisis. It prompted an emergency expedition
by a U.S. team the following year to measure the damage and try to
understand its cause.
Prof. Robert de Zafra of what was then the Department of Physics led Stony Brook's participation in the National Ozone Expeditions of 1986 and 1987. Using instrumentation designed by Prof. de Zafra and Research Associate Alan Parrish, based on the application of millimeter-wave molecular astronomy to the detection of molecules in the earth's own atmosphere, Stony Brook's research team, including Professor Philip Solomon of what was then the Department of Earth and Space Sciences, provided key measurements detecting and quantitatively measuring the presence of chlorine oxide (ClO) molecules in unprecedented quantities in the lower stratosphere over Antarctica.
These results constituted a 'smoking gun' indicating that the accumulation of chlorofluorocarbons (CFCs) in the stratosphere - resulting from their proliferation in such universals of modern life as aerosols, refrigerants and the manufacture of Styrofoam - and their degradation by the very same UV radiation the ozone layer protects us against - was the cause of the growing seasonal "ozone hole" over Antarctica. Prof. de Zafra led numerous additional trips to the McMurdo Sound research station in Antarctica from the mid-1980s to the late-1990s, as well as to the South Pole itself, and to Thule, Greenland, and Spitzbergen in the far northern Arctic. At the campus, he continues as a Research Professor of Physics (and emeritus teaching faculty member) to incorporate new technical advances into his ground-based remote sensing equipment, which have made it the most sensitive in the world for ground-based millimeter-wave atmospheric spectroscopy. Observational research in stratospheric chemistry and dynamics is now being continued, with collaborators from University of Rome, at a new high altitude observatory near the Matterhorn.
The public policy implications of this important work, in the context of the larger efforts of which it was a part, led to the adoption in 1987 of the Montreal Protocol on Substances That Deplete the Ozone Layer, the international treaty designed to protect the ozone layer from depletion by phasing out the production of CFCs and other ozone-depleting substances.
Prof. de Zafra received the nation's Antarctic Service Medal in 1987 in recognition of "valuable contributions to exploration and scientific achievement under the U.S. Antarctic Research Program" and subsequently served three terms on the International Ozone Commission, a term on the National Research Council's Polar Research Board and a term on the International Radiation Commission. A five-mile-long mountain ridgeline protruding through the Antarctic ice was named in his honor near McMurdo Station in 2001.
Grateful acknowledgment is made for material adapted from the Website of the Department of Physics and Astronomy.