February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 1, NUMBER 6, DECEMBER 1988
"Observations of the Nighttime Abundance of OClO in the Winter
Stratosphere Above Thule, Greenland," S. Solomon (Aeronomy Lab., NOAA/ERL,
Boulder CO 80303), G.H. Mount et al., Science, 242(4878),
550-555, Oct. 28, 1988.
Observations made using direct light from the moon in February 1988 revealed
nighttime chlorine dioxide abundances less than those obtained in Antarctica but
exceeding model predictions based on homogeneous (gas-phase) chemistry by about
a factor of 10. The observed time scale for formation of OClO after sunset
strongly supports the current understanding of its diurnal chemistry, suggesting
heterogeneous (surface) reactions due to polar stratospheric clouds can occur in
the Arctic, providing a mechanism for possible Arctic ozone destruction.
"Observations of Stratospheric NO2 and O3 at Thule, Greenland,"
G.H. Mount (address immed. above), S. Solomon et al., ibid., 555-558.
Total column abundances were measured in February using scattered sunlight
and direct light from the moon. Lower O3 values were observed when the center of
the Arctic polar vortex was closest to Thule, probably indicating that O3 levels
decrease due to dynamical processes near the vortex center, a fact that should
be considered when deriving O3 trends. NO2 levels were also lowest in the vortex
center, suggesting significant heterogeneous photochemistry takes place
during the Arctic winter as it does in the Antarctic.
"In Situ Northern Mid-Latitude Observations of ClO, O3, and BrO in
the Wintertime Lower Stratosphere," W.H. Brune (Dept. Meteorol., Penn.
State Univ., Univ. Pk. PA 16802), D.W. Toohey et al., ibid., 558-562.
Several related atmospheric species were measured in the lower stratosphere
with instruments mounted on the NASA ER-2 aircraft in February 1988, to test
photochemical theories linking chlorofluorocarbon derivatives to O3 depletion at
high latitudes in springtime. On the flight from Moffett Field, California to
Great Slave Lake, Canada, levels of ClO and O3 were highly correlated at all
scales, and both showed an abrupt change in character at 54 ĚN latitude.
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