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Title: Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

Abstract

A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approachmore » reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.« less

Authors:
; ; ; ;  [1]
  1. (Univ. of Arizona, Tucson (United States))
Publication Date:
OSTI Identifier:
6381608
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the Atmospheric Sciences; (United States); Journal Volume: 50:8
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; AEROSOLS; OPTICAL DEPTH CURVE; OZONE; ALGORITHMS; ARIZONA; ATMOSPHERIC CHEMISTRY; CALCULATION METHODS; COMPUTERIZED SIMULATION; HAWAII; VALIDATION; VOLCANIC GASES; CHEMISTRY; COLLOIDS; DEVELOPED COUNTRIES; DIAGRAMS; DISPERSIONS; FLUIDS; GASES; MATHEMATICAL LOGIC; NORTH AMERICA; SIMULATION; SOLS; TESTING; USA; 540120* - Environment, Atmospheric- Chemicals Monitoring & Transport- (1990-)

Citation Formats

Flittner, D.E., Herman, B.M., Thome, K.J., Simpson, J.M., and Reagan, J.A. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band. United States: N. p., 1993. Web. doi:10.1175/1520-0469(1993)050<1113:TOAAOD>2.0.CO;2.
Flittner, D.E., Herman, B.M., Thome, K.J., Simpson, J.M., & Reagan, J.A. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band. United States. doi:10.1175/1520-0469(1993)050<1113:TOAAOD>2.0.CO;2.
Flittner, D.E., Herman, B.M., Thome, K.J., Simpson, J.M., and Reagan, J.A. 1993. "Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band". United States. doi:10.1175/1520-0469(1993)050<1113:TOAAOD>2.0.CO;2.
@article{osti_6381608,
title = {Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band},
author = {Flittner, D.E. and Herman, B.M. and Thome, K.J. and Simpson, J.M. and Reagan, J.A.},
abstractNote = {A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.},
doi = {10.1175/1520-0469(1993)050<1113:TOAAOD>2.0.CO;2},
journal = {Journal of the Atmospheric Sciences; (United States)},
number = ,
volume = 50:8,
place = {United States},
year = 1993,
month = 4
}
  • Standard measurements of total column ozone are made in the ultraviolet portion of the spectrum in the Huggins bands, using wavelengths between 305 and 340 nm. Dobson spectrophotometers, Brewer spectrophotometers, and M-83 filter ozonometers are standard ground-based instruments for these ultraviolet total column ozone measurements. They each use wavelength pairs to get a differential absorption between strong and relatively weaker portions of the ozone spectrum. In this paper the authors compare Chappuis band ozone measurements using the multi-filter rotating shadowband radiometer with Dobson or Brewer spectrophotometer measurements, not only on a seasonal basis, but on a daily basis as well.
  • This paper presents a comparison of Chappuis band ozone measurements using the multi-filter rotating shadowband radiometer with Dobson or Brewer spectrophotometer measurements at the same sites, not only on a seasonal basis, but on a daily basis, as well.
  • New global diabatic potential energy surfaces of the electronic states {sup 1}B{sub 1} and {sup 1}A{sub 2} of ozone and the non-adiabatic coupling surface between them are constructed from electronic structure calculations. These surfaces are used to study the visible photodissociation in the Chappuis band by means of quantum mechanical calculations. The calculated absorption spectrum and its absolute intensity are in good agreement with the experimental results. A vibrational assignment of the diffuse structures in the Chappuis band system is proposed on the basis of the nodal structures of the underlying resonance states.
  • Large amounts of SO{sub 2} injected into the stratosphere by the El Chichon volcanic eruption greatly enhanced the sulfuric acid aerosol loading. According to laboratory studies, the increase in aerosol surface area would lead to a loss of ozone. Radiation measurements from the solar backscatter ultraviolet spectroradiometer are used to probe the absorbing and scattering properties of the stratosphere after the eruption. The backscattered radiation is enhanced for wavelengths greater than 290 nm, with a peak at about 302 nm. The enhancements associated with aerosol backscattering and ozone change can be separated. A decrease in column ozone of 8 tomore » 30 Dobson units was deduced within the aerosol layer at an altitude between 20 and 30 km following the month of the eruption. 26 refs., 10 figs.« less
  • We apply a simple model for the photodissociation absorption spectra of bent symmetric triatomic molecules to the Wulf--Chappuis band system of ozone (10 000--22 000 cm{sup {minus}1} ) to assign the electronic states and the diffuse vibrational bands involved. The conical intersection between the two lowest {sup 1}{ital A}{double prime} states is treated in an approximate way, and the role of the lowest excited triplet states is explored. The results indicate that the Wulf band is probably due to the {sup 3}{ital A}{sub 2} state of ozone which gains intensity through spin--orbit coupling. The 1 {sup 1}{ital A}{double prime} ({supmore » 1}{ital A}{sub 2}) state gives rise to the featureless red wing of the Chappuis band. Most of the structure in the Chappuis band is reproduced in the model and is due to the 2 {sup 1}{ital A}{double prime} ({sup 1}{ital B}{sub 1}) state as was previously supposed. A more complete treatment of the conical intersection and nonadiabatic effects will be necessary to quantitatively reproduce all features of the experimental spectra.« less