Tropospheric Ozone Profile Retrievals from an Airborne Ultra- violet/Visible Spectrometer

Abstract. We present a novel technique to retrieve ozone profiles, and especially, tropospheric ozone (O3) from airborne Ultraviolet-Visible (UV) spectrometer measurements. The profile retrieval is possible by viewing a variety of zenith angles from down-looking and up-looking directions, taking advantage of O3 absorption in the Huggins (300-340 nm) and the Chappuis bands (530-650 nm). Measurements are normalized to measured direct irradiances or zenith-sky radiances so our approach does not require the use of a solar reference. This technique is especially sensitive to tropospheric O3 below and ~10 km above the aircraft with a resolution of ~2-6 km and is sensitive to lower and middle stratospheric O3 with a vertical resolution of 8-15 km. It can measure tropospheric O3 at a horizontal resolution of 2 km ´ 2 km or even higher and is therefore well suited for regional air quality studies and validation of satellite measurements. 1