Preprints
https://doi.org/10.5194/acpd-15-25907-2015
https://doi.org/10.5194/acpd-15-25907-2015
24 Sep 2015
 | 24 Sep 2015
Status: this preprint was under review for the journal ACP but the revision was not accepted.

Simultaneous Retrievals of Polar Mesospheric Clouds (PMCs) with Ozone from OMI UV measurements

J. Bak, X. Liu, J. H. Kim, M. T. Deland, and K. Chance

Abstract. The presence of polar mesospheric clouds (PMCs) at high latitudes could affect the retrieval of ozone profiles using backscattered ultraviolet (BUV) measurements. PMC-induced errors in ozone profile retrievals from Ozone Monitoring Instrument (OMI) BUV measurements are investigated through comparisons with Microwave Limb Sounder (MLS) ozone measurements. This comparison demonstrates that the presence of PMCs leads to systematic biases at altitudes above 6 hPa in summer high latitudes; the biases increase from ~ −2 % at 2 hPa to ~ −20 % at 0.5 hPa on average, and are significantly correlated with brightness of PMCs. Sensitivity studies show that the radiance sensitivity to PMCs strongly depends on wavelengths, increasing by a factor of ~ 4 from 300 to 265 nm. It also strongly depends on the PMC scattering, thus depending on viewing geometry. The optimal estimation-based retrieval sensitivity analysis shows that PMCs located at 80–85 km have the greatest effect on ozone retrievals at ~ 0.2 hPa (~ 60 km), where the retrieval errors range from −2.5 % with PMC optical depth (POD) of 10−4 to −20 % with 10−3 at back scattering angles, and the impacts increase by a factor of ~ 5 at forward scattering angles due to stronger PMC sensitivities. To reduce the interference of PMCs on ozone retrievals, we perform simultaneous retrievals of POD and ozone with a loose constraint of 10−3 for POD, which results in retrieval errors of 1–4 × 10−4. It is demonstrated that the negative bias of OMI ozone retrievals relative to MLS could be improved by including the PMC in the forward model calculation and retrieval.

J. Bak, X. Liu, J. H. Kim, M. T. Deland, and K. Chance
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
J. Bak, X. Liu, J. H. Kim, M. T. Deland, and K. Chance
J. Bak, X. Liu, J. H. Kim, M. T. Deland, and K. Chance

Viewed

Total article views: 1,526 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
1,124 286 116 1,526 95 104
  • HTML: 1,124
  • PDF: 286
  • XML: 116
  • Total: 1,526
  • BibTeX: 95
  • EndNote: 104
Views and downloads (calculated since 24 Sep 2015)
Cumulative views and downloads (calculated since 24 Sep 2015)
Latest update: 28 Mar 2024
Download
Short summary
This work demonstrated the interference of tenuous PMCs on OMI ozone profile retrievals above 6hPa. The presence of PMCs leads to the systematic biases of -2% at 2hPa and -20% at 0.5hPa in OMI retrievals, which are significantly correlated with brightness of PMCs. We perform simultaneous retrievals of PMC optical depth with ozone using optimal estimation technique, to reduce the interference on ozone profile retrievals. As a result, the negative OMI biases are reduced to within ±10%.
Altmetrics