Premium
A 3D simulation of the early winter distribution of reactive chlorine in the north polar vortex
Author(s) -
Douglass A.,
Rood R.,
Waters J.,
Froidevaux L.,
Read W.,
Elson L.,
Geller M.,
Chi Y.,
Cerniglia M.,
Steenrod S.
Publication year - 1993
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 - 10.1029/93gl01586
Subject(s) - anticyclone , polar vortex , microwave limb sounder , chlorine , atmospheric sciences , middle latitudes , vortex , latitude , shearing (physics) , polar , stratosphere , environmental science , ozone depletion , climatology , geology , meteorology , materials science , physics , geodesy , geotechnical engineering , astronomy , metallurgy
Early in December 1991, high values of ClO are seen by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite at latitudes south of areas of temperatures cold enough to form polar stratospheric clouds (PSC's). A three dimensional simulation shows that the heterogeneous conversion of chlorine reservoirs to reactive chlorine on the surfaces of PSC's (processing) takes place at high latitudes. Often the “processed” air must be transported to lower latitudes, where the reactive chlorine is photochemically converted to ClO, to be observed by MLS. In this simulation, one incidence of cold temperatures is associated with an anticyclone, and a second with a cyclone. The transport of processed air associated with the anticyclone is marked by shearing; a decrease in the maximum of the processed air is accompanied by growth of the area influenced by the processing. In contrast, the air processed in the cyclonic event spreads more slowly. This shows that transport and shearing is a crucial element to the evolution of reactive chlorine associated with a processing event. In particular, transport and shearing, as well as photochemical processes, can cause variations in observed ClO.