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Inclusion of the second Umkehr in the conventional Umkehr retrieval analysis as a means of improving ozone retrievals in the upper stratosphereThe Umkehr method for retrieving the gross features of the vertical ozone distribution requires measurements of the ratio of zenith-sky radiances at two wavelengths in the near-UV region while the solar zenith angle (SZA) changes from 60 to 90 degrees. A Brewer spectrophotometer was used for taking such measurements extending the SZA range down to 96 degrees. Analyzed data from the Spring of 1991 imply that observations at twilight are of great significance in improving ozone retrievals in the upper stratosphere. Judged by the variance reduction for Umkehr layers 9 to 12 (25-30 percent for layer 11) and the increase in separation and amplitude of the averaging kernels for the relevant layers, the ozone retrievals in the upper stratosphere are shown to be in better agreement with climatological means.
Document ID
Document Type
Conference Paper
Gioulgkidis, Konstantinos (University of Western Ontario London Ontario, Canada)
Lowe, Robert P. (University of Western Ontario London Ontario, Canada)
Mcelroy, C. Tom (University of Western Ontario London Ontario, Canada)
Date Acquired
September 6, 2013
Publication Date
April 1, 1994
Publication Information
Publication: NASA. Goddard Space Flight Center, Ozone in the Troposphere and Stratosphere, Part 2
Subject Category
Distribution Limits
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19950004531Analytic PrimaryWorkshop on the Analysis of Interplanetary Dust Particles