Identification

Title

Ground-based direct-sun DOAS and airborne MAX-DOAS measurements of the collision-induced oxygen complex, Oâ‚‚Oâ‚‚, absorption with significant pressure and temperature differences

Abstract

The collision-induced O₂ complex, O₂O₂, is a very important trace gas for understanding remote sensing measurements of aerosols, cloud properties and atmospheric trace gases. Many ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of the O₂O₂ optical depth require correction factors of 0.75 ± 0.1 to reproduce radiative transfer modeling (RTM) results for a nearly pure Rayleigh atmosphere. One of the potential causes of this discrepancy is uncertainty in laboratory-measured O₂O₂ absorption cross section temperature and pressure dependencies due to difficulties in replicating atmospheric conditions in the laboratory environment. This paper presents ground-based direct-sun (DS) and airborne multi-axis (AMAX) DOAS measurements of O₂O₂ absorption optical depths under actual atmospheric conditions in two wavelength regions (335--390 and 435--490 nm). DS irradiance measurements were made by the Washington State University research-grade Multi-Function Differential Spectroscopy Instrument instrument from 2007 to 2014 at seven sites with significant pressure (778 to 1013 hPa) and O₂O₂ profile-weighted temperature (247 to 275 K) differences. Aircraft MAX-DOAS measurements were conducted by the University of Colorado (CU) AMAX-DOAS instrument on 29 January 2012 over the Southern Hemispheric subtropical Pacific Ocean. Scattered solar radiance spectra were collected at altitudes between 9 and 13.2 km, with O₂O₂ profile-weighted temperatures of 231 to 244 K and nearly pure Rayleigh scattering conditions. Due to the well-defined DS air-mass factors during ground-based measurements and extensively characterized atmospheric conditions during the aircraft AMAX-DOAS measurements, O₂O₂ "pseudo" absorption cross sections, σ, are derived from the observed optical depths and estimated O₂O₂ column densities. Vertical O₂O₂ columns are calculated from the atmospheric sounding temperature, pressure and specific humidity profiles.

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document

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https://n2t.org/ark:/85065/d7jw8g1b

codeSpace

Dataset language

eng

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geoscientificInformation

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Text

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title

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publication

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2016-01-01T00:00:00Z

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publication

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2015-02-15T00:00:00Z

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Copyright Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License5

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None

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OpenSky Support

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UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

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opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

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OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata date

2025-12-26T03:16:17.421783

Metadata language