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Seasonal variation of atmospheric nitric acid over the South Pole in 1992We conducted year-around measurements of mid infrared atmospheric emission over the South Pole in 1992. We were able to observe a large seasonal change of the total column of nitric acid (HNO3) vapor. During the summer the HNO3 column abundance was about 2 x 10(exp 16) molecules/sq cm. There was a small increase in the fall. A rapid decrease of 50% was observed in late June, soon after the stratospheric temperature reached the threshold for formation of type I polar stratospheric clouds (PSCs). By early July, the stratospheric temperature was cold enough to form type II PSCs, and the HNO3 column decreased to 7 x 10(exp 15) molecules/sq cm. Measured nitric acid values in the spring remained extremely low even after the stratosphere warmed well above PSC temperatures. This may indicate permanent removal of HNO3 by gravitational settling, or long-term sequestering in large particles. Normal summer values were not observed until the vortex dissipated and allowed the lateral transport of HNO3 to the south polar region.
Document ID
19950055713
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Allen, Renate Van
(University of Denver, Denver, CO United States)
Liu, XU
(University of Denver, Denver, CO United States)
Murcray, Frank J.
(University of Denver, Denver, CO United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1995
Publication Information
Publication: Geophysical Research Letters
Volume: 22
Issue: 1
ISSN: 0094-8276
Subject Category
Meteorology And Climatology
Accession Number
95A87312
Funding Number(s)
CONTRACT_GRANT: NSG-1432
CONTRACT_GRANT: NSF OPP-92-19209
Distribution Limits
Public
Copyright
Other

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