Abstract
Abstract. A new method is presented to determine vertical ozone profiles from measurements of spectral global (direct Sun plus upper hemisphere) irradiance in the ultraviolet. The method is similar to the widely used Umkehr technique, which inverts measurements of zenith sky radiance. The procedure was applied to measurements of a high-resolution spectroradiometer installed near the centre of the Greenland ice sheet. Retrieved profiles were validated with balloon-sonde observations and ozone profiles from the space-borne Microwave Limb Sounder (MLS). Depending on altitude, the bias between retrieval results presented in this paper and MLS observations ranges between −5 and +3 %. The magnitude of this bias is comparable, if not smaller, to values reported in the literature for the standard Dobson Umkehr method. Total ozone columns (TOCs) calculated from the retrieved profiles agree to within 0.7±2.0 % (±1σ) with TOCs measured by the Ozone Monitoring Instrument on board the Aura satellite. The new method is called the Global-Umkehr method.
Highlights
The Umkehr method for determining the vertical distribution of ozone in the atmosphere was first introduced in the 1930s (Götz et al, 1934) and is routinely applied to measurements taken with Dobson (e.g. Dütsch, 1959; Mateer and DeLuisi, 1992; Petropavlovskikh et al, 2005) and Brewer (McElroy and Kerr, 1995; Petropavlovskikh et al, 2011) spectrophotometers
This suggests that a large portion of the observed retrieval–Microwave Limb Sounder (MLS) differences can be attributed to actual changes in the ozone profile over the time periods relevant for these comparisons
Further analysis revealed that the difference between the MLS 1 and MLS 2 data sets depends on the time at which the daily MLS observation takes place
Summary
The Umkehr method for determining the vertical distribution of ozone in the atmosphere was first introduced in the 1930s (Götz et al, 1934) and is routinely applied to measurements taken with Dobson (e.g. Dütsch, 1959; Mateer and DeLuisi, 1992; Petropavlovskikh et al, 2005) and Brewer (McElroy and Kerr, 1995; Petropavlovskikh et al, 2011) spectrophotometers. We explore using a similar optimal statistical approach to obtain vertical ozone information from measurements of spectrally resolved global irradiance, i.e. the irradiance received by a horizontal cosine collector from direct Sun and sky (upper hemisphere, from zenith to horizon). Such measurements were started by several groups in the early 1990s to monitor changes in UV radiation at the Earth’s surface. The proposed method has the potential to make these long-term data sets available for assessing vertical ozone information in an approach similar to standard zenith-sky Umkehr retrievals. This is interesting for locations where zenith-sky observations are not available
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
