This web page's content and links are no longer actively maintained. It is available for reference purposes only. NASA Official: Luke Oman

UARS Instrument Timeline

1839 C. Schonbein discovers ozone.

1881 W. Hartley discovers that ozone is a cause of solar UV absorption.

1924 G. Dobson builds first spectrophotometer and notes stratospheric ozone changes near weather fronts.

1950's V2 rocket data determine the temperature structure of the upper stratosphere and mesosphere.

1957 Dobson instruments stationed around the world; ozone climatology determined.

1960's Many ozone chemical reactions determined.

1973 R. Stolarski and R. Cicerone propose stratospheric chlorine catalytic cycle.

1974 F.S. Rowland and M. Molina hypothesize that CFC's entering the stratosphere will release reactive chlorine that will destroy ozone.

1976 J. Anderson and colleagues make first measurement of CIO in the stratosphere.

1984 J. Farman discovers growing ozone hole over the Antarctic. From September to mid-November, ozone concentrations over Halley Bay, Antarctica, declined 40 percent from levels measured during the 1980's.

1985 NASA's Nimbus 7 TOMS maps the extent of the Antarctic ozone hole. Ozone hole covers 12 million square kilometers.

1986 S. Solomon and colleagues propose that reactions on the surface of polar stratospheric clouds involving stratospheric chlorine reservoir gases lead to formation of the Antarctic ozone hole. Ground-based observations show high levels of chlorine radicals in the Antarctic stratosphere.

1987 Specially equipped NASA aircraft show that the ozone hole is caused by stratospheric chlorine. Montreal Protocol restricting the production of CFC's signed. Ozone hole expands to 20 million square kilometers.

1991 June, Mt. Pinatubo erupts. September, UARS deployed from Space Shuttle Discovery. CFC amounts in the troposphere begin to level off.

1995 M. Molina, F.S. Rowland, and P. Crutzen win Nobel Prize in Chemistry for work on atmospheric catalytic destruction of ozone. Ozone hole stabilizes at about 24 million square kilometers (roughly the area of North America).

1996 Complete ban on industrial production of CFC's takes effect. Record ozone loss occurs in the Arctic.

1998 UARS measurements show that chlorine amounts in the upper stratosphere are beginning to level off.

The Future Will ozone levels return to normal as chlorine leaves the stratosphere?

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UARS Home Page

Web Curator: Monica Todirita, (Science Systems Applications, Inc) (todirita@umpgal.gsfc.nasa.gov)

Responsible NASA organization/official: Dr. Luke Oman, Atmospheric Chemistry and Dynamics Laaboratory

Last modified: March 08, 2017

1839	C. Schonbein discovers ozone.
1881	W. Hartley discovers that ozone is a cause of solar UV absorption.
1924	G. Dobson builds first spectrophotometer and notes stratospheric ozone changes near weather fronts.
1950's	V2 rocket data determine the temperature structure of the upper stratosphere and mesosphere.
1957	Dobson instruments stationed around the world; ozone climatology determined.
1960's	Many ozone chemical reactions determined.
1973	R. Stolarski and R. Cicerone propose stratospheric chlorine catalytic cycle.
1974	F.S. Rowland and M. Molina hypothesize that CFC's entering the stratosphere will release reactive chlorine that will destroy ozone.
1976	J. Anderson and colleagues make first measurement of CIO in the stratosphere.
1984	J. Farman discovers growing ozone hole over the Antarctic. From September to mid-November, ozone concentrations over Halley Bay, Antarctica, declined 40 percent from levels measured during the 1980's.
1985	NASA's Nimbus 7 TOMS maps the extent of the Antarctic ozone hole. Ozone hole covers 12 million square kilometers.
1986	S. Solomon and colleagues propose that reactions on the surface of polar stratospheric clouds involving stratospheric chlorine reservoir gases lead to formation of the Antarctic ozone hole. Ground-based observations show high levels of chlorine radicals in the Antarctic stratosphere.
1987	Specially equipped NASA aircraft show that the ozone hole is caused by stratospheric chlorine. Montreal Protocol restricting the production of CFC's signed. Ozone hole expands to 20 million square kilometers.
1991	June, Mt. Pinatubo erupts. September, UARS deployed from Space Shuttle Discovery. CFC amounts in the troposphere begin to level off.
1995	M. Molina, F.S. Rowland, and P. Crutzen win Nobel Prize in Chemistry for work on atmospheric catalytic destruction of ozone. Ozone hole stabilizes at about 24 million square kilometers (roughly the area of North America).
1996	Complete ban on industrial production of CFC's takes effect. Record ozone loss occurs in the Arctic.
1998	UARS measurements show that chlorine amounts in the upper stratosphere are beginning to level off.
The Future	Will ozone levels return to normal as chlorine leaves the stratosphere?