Optical Extinction Spectroscopy at Moderate Resolution: Insights into Problems of Weak Absorption Bands

Abstract

Sunphotometry is a common technique for characterizing aerosol properties. Photometers used for these measurements have a series of narrow-band filters that are chosen to avoid molecular absorption features, except for the very broad Chappuis ozone band centered near 600 nm. This note reports on a set of moderate resolution spectra that were used to derive optical depth every 10 nm throughout the visible and near infrared. The usefulness of this type of continuous optical depth spectrum for selecting sunphotometer filters and the importance of often-ignored, weak molecular bands near 600 nm are discussed.