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Geometrical path length probability density functions of the skylight transmitted by midlatitude cloudy skies: Some case studies
Author(s) -
Veitel H.,
Funk O.,
Kurz C.,
Platt U.,
Pfeilsticker K.
Publication year - 1998
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 - 10.1029/98gl02506
Subject(s) - skylight , cirrus , middle latitudes , zenith , meteorology , optical depth , absorption (acoustics) , environmental science , atmospheric sciences , physics , optics , geography , archaeology , aerosol
Examples of inferred probability density functions of geometrical path lengths (PDF‐GP) for zenith‐scattered skylight transmitted by cloudy skies at midlatitude (50°N, 8.2°E) are reported. The method relies on high resolution spectroscopy of the O 2 A‐band (760nm–780nm) absorption in the transmitted skylight, and an·inverse Laplace transform to recover the PDF‐GP from the absorption strengths of a set of A‐band absorption lines. Some examples of a larger set of measurements are presented and discussed in detail. These examples include PDF‐GPs for typical midlatitude summer (fair weather Cumulus) and winter (Stratus) cloudiness. Moreover, two cloud observations with largely enhanced O 2 A‐band absorptions (up to a factor of 7 implying a mean geometrical path length of about 116 km) are discussed, namely the PDF‐GPs of thunderstorm clouds (Cumulonimbus, Cb) and of clouds formed in a cold front (Stratocumulus, Sc; Altostratus, As; Nimbostratus, Ns; Cirrus, Ci).