Optical and physical properties of stratospheric aerosols from balloon measurements in the visible and near-infrared domains. II. Comparison of extinction, reflectance, polarization, and counting measurements.
The physical properties of stratospheric aerosols can be retrieved from optical measurements involving extinction, radiance, polarization, and counting. We present here the results of measurements from the balloonborne instruments AMON, SALOMON, and RADIBAL, and from the French Laboratoire de Météorologie Dynamique and the University of Wyoming balloonborne particle counters. A cross comparison of the measurements was made for observations of background aerosols conducted during the polar winters of February 1997 and January-February 2000 for various altitudes from 13 to 19 km. On the one band, the effective radius and the total amount of background aerosols derived from the various sets of data are similar and are in agreement with pre-Pinatubo values. On the other hand, strong discrepancies occur in the shapes of the bimodal size distributions obtained from analysis of the raw measurement of the various instruments. It seems then that the log-normal assumption cannot fully reproduce the size distribution of background aerosols. The effect ofthe presence of particular aerosols on the measurements is discussed, and a new strategy for observations is proposed.
Renard
Jean-Baptiste
JB
Laboratoire de Physique et Chimie de l'Environnement/Centre National de la Recherche Scientifique, 3A Avenue de la Recherche Scientifique, F-45071 Orléans 2, France. jbrenard@cnrs-orleans.fr
Berthet
Gwenaël
G
Robert
Claude
C
Chartier
Michel
M
Pirre
Michel
M
Brogniez
Colette
C
Herman
Maurice
M
Verwaerde
Christian
C
Balois
Jean-Yves
JY
Ovarlez
Joëlle
J
Ovarlez
Henri
H
Crespin
Jacques
J
Deshler
Terry
T