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Intercomparison of the influence of tropospheric clouds on UV‐visible absorptions Detected during the NDSC Intercomparison Campaign at OHP in June 1996
Author(s) -
Pfeilsticker K.,
Arlander D. W.,
Burrows J. P.,
Erle F.,
Gil M.,
Goutail F.,
Hermans C.,
Lambert J.C.,
Platt U.,
Pommereau J.P.,
Richter A.,
Sarkissian A.,
Van Roozendael M.,
Wagner T.,
Winterrath T.
Publication year - 1999
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 - 10.1029/1999gl900198
Subject(s) - zenith , troposphere , sky , stratosphere , atmospheric sciences , environmental science , night sky , spectrometer , meteorology , physics , optics , astronomy
The influence of tropospheric clouds on zenith sky light (or brief ZSL‐DOAS) measurements of stratospheric gases is investigated. From a large set of intercomparison studies including six simultaneously operated UV/visible spectrometers, the zenith sky absorptions of O 3 , O 4 , NO 2 , and H 2 O are found to increase considerably under the investigated Cumulonimbus (Cb) cloud. The accuracy of the inferred visible O 3 absorptions, however, are affected by interfering H 2 O absorptions. The increased cloudy sky absorptions are attributed to increased pathlengths due to multiple Mie scattering and hence interstitial gaseous absorptions inside the cloud. The absorptions detected for chemically inert gases like O 4 (and H 2 O) are found to be inconsistent with those detected for NO 2 and O 3 . This finding indicates that O 3 and NO 2 are modified by cloud related transport or chemical processes.