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SAGE II observations of polar stratospheric clouds near 50°N January 31–February 2, 1989
Author(s) -
Pitts M. C.,
Poole L. R.,
McCormick M. P.
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i004p00405
Subject(s) - atmospheric sciences , polar , environmental science , latitude , ozone depletion , stratosphere , arctic , extinction (optical mineralogy) , aerosol , climatology , ozone , ozone layer , high latitude , middle latitudes , meteorology , geology , geography , physics , oceanography , astronomy , paleontology
Polar stratospheric clouds (PSCs) form at very cold temperatures which typically occur only at high latitudes during local winter. However, meteorological circumstances in the Arctic during late January 1989 led to PSC formation unusually far to the south, at latitudes (near 50°N) being sampled during the period (January 31–February 2) by the orbiting SAGE II instrument. These unusual PSC sightings and the evolution of meteorological conditions which produced the episode are described. Profiles of SAGE II extinction measurements at 0.525 and 1.02 μm show clear signatures of PSCs and indicate that the cloud particles were considerably larger than the background aerosol. It is most important to note that the clouds were sighted at a latitude where there was extensive sunlight, thus increasing the likelihood of ozone loss both locally and downstream due to enhancements in reactive chlorine expected from heterogeneous chemical processing within the PSCs.