Background Stratospheric Aerosol Investigations Using Multi-Color Wide-Field Measurements of the Twilight Sky

TL;DR

This study uses multi-wavelength twilight sky measurements to analyze stratospheric aerosols, revealing their size distribution and scattering properties up to 35 km altitude, with implications for atmospheric monitoring.

Contribution

It introduces a novel multi-color all-sky measurement method during twilight to characterize stratospheric aerosols and retrieve their size distribution parameters.

Findings

Aerosol scattering significantly increases at longer wavelengths.

Median aerosol particle radius is approximately 0.08 microns.

The aerosol size distribution width is about 1.5-1.6.

Abstract

First results of multi-wavelength measurements of the twilight sky background using all-sky camera with RGB-color CCD conducted in spring and summer of 2016 in central Russia (55.2 deg N, 37.5 deg E) are discussed. They show the effect of aerosol scattering at altitudes up to 35 km which significantly increases to the long-wave range (624 nm, R channel). Analysis of sky color behavior during the light period of twilight with account of ozone Chappuis absorption allows retrieving the angle dependencies of scattering on the stratospheric aerosol particles. This is used to find the parameters of lognormal size distribution: median radius about 0.08 microns and width 1.5-1.6 for stratospheric altitude range.