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On the influence of tropospheric clouds on zenith‐scattered‐light measurements of stratospheric species
Author(s) -
Erle F.,
Pfeilsticker K.,
Platt U.
Publication year - 1995
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 - 10.1029/95gl02789
Subject(s) - troposphere , zenith , solar zenith angle , atmospheric sciences , stratosphere , radiative transfer , absorption (acoustics) , environmental science , physics , optics
Examples for the influence of tropospheric clouds on the ground‐based measurement of stratospheric species using the DOAS‐technique (Differential Optical Absorption Spectroscopy) are reported. At Camborne/Great Britain (50.216°N, 5.316°W) on Sept. 11–15, 1994, episodic enhancement of absorption lines of O 4 , H 2 O, O 3 and NO 2 were observed in coincidence with tropospheric clouds being in the instrumental field of view (1.1° full angle). At a solar zenith angle (SZA) of 88°, absorption enhancements up to roughly a factor of 3 were detected for the tropospheric species O 4 and H 2 O and the tropospheric fractions of the total column of O 3 and NO 2 . The additional absorptions in the visible spectral range are probably caused by multiple Mie‐scattering in tropospheric clouds. For our conditions, a tropospheric light path enhancement (TLPE) of 135±40 km can be inferred, being largely independent of SZA. This observation has several important implications for the atmospheric radiative transport, which are briefly discussed.