Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO
The Infrared Atmospheric Sounder Instrument (IASI) allows global coverage with very high spatial resolution and its measurements are promising for long-term ozone monitoring. In this study, Microwave Limb Sounder (MLS) O<sub>3</sub> profiles and IASI O<sub>3</sub> partial...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2018-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/6939/2018/acp-18-6939-2018.pdf |
| _version_ | 1828465074157649920 |
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| author | H. Peiro E. Emili D. Cariolle D. Cariolle B. Barret E. Le Flochmoën |
| author_facet | H. Peiro E. Emili D. Cariolle D. Cariolle B. Barret E. Le Flochmoën |
| author_sort | H. Peiro |
| collection | DOAJ |
| description | The Infrared Atmospheric Sounder Instrument (IASI) allows global coverage
with very high spatial resolution and its measurements are promising for
long-term ozone monitoring. In this study, Microwave Limb Sounder (MLS) O<sub>3</sub>
profiles and IASI O<sub>3</sub> partial columns (1013.25–345 hPa) are assimilated in a chemistry transport model to produce 6-hourly analyses of tropospheric
ozone for 6 years (2008–2013). We have compared and evaluated the IASI-MLS analysis and the MLS analysis to assess the added value of IASI measurements.
<br><br>
The global chemical transport model MOCAGE (MOdèle de Chimie
Atmosphérique à Grande Echelle) has been used with a linear ozone
chemistry scheme and meteorological forcing fields from ERA-Interim (ECMWF
global reanalysis) with a horizontal resolution of
2° × 2° and 60 vertical levels. The MLS and IASI
O<sub>3</sub> retrievals have been assimilated with a 4-D variational algorithm to constrain stratospheric and tropospheric ozone respectively. The ozone
analyses are validated against ozone soundings and tropospheric column
ozone (TCO) from the OMI-MLS residual method. In addition, an Ozone ENSO
Index (OEI) is computed from the analysis to validate the TCO variability
during the ENSO events.
<br><br>
We show that the assimilation of IASI reproduces the variability of
tropospheric ozone well during the period under study. The variability deduced
from the IASI-MLS analysis and the OMI-MLS measurements are similar for the
period of study. The IASI-MLS analysis can reproduce the extreme oscillation
of tropospheric ozone caused by ENSO events over the tropical Pacific Ocean,
although a correction is required to reduce a constant bias present in the
IASI-MLS analysis. |
| first_indexed | 2024-12-11T03:25:49Z |
| format | Article |
| id | doaj.art-b0ddf9f300944a1db1172f0875b80b87 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-11T03:25:49Z |
| publishDate | 2018-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-b0ddf9f300944a1db1172f0875b80b872022-12-22T01:22:32ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242018-05-01186939695810.5194/acp-18-6939-2018Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSOH. Peiro0E. Emili1D. Cariolle2D. Cariolle3B. Barret4E. Le Flochmoën5CECI, Université de Toulouse, Cerfacs, CNRS, Toulouse, FranceCECI, Université de Toulouse, Cerfacs, CNRS, Toulouse, FranceCECI, Université de Toulouse, Cerfacs, CNRS, Toulouse, FranceMétéo-France, Toulouse, FranceLaboratoire d'Aérologie, Université de Toulouse, CNRS, UPS, Toulouse, FranceLaboratoire d'Aérologie, Université de Toulouse, CNRS, UPS, Toulouse, FranceThe Infrared Atmospheric Sounder Instrument (IASI) allows global coverage with very high spatial resolution and its measurements are promising for long-term ozone monitoring. In this study, Microwave Limb Sounder (MLS) O<sub>3</sub> profiles and IASI O<sub>3</sub> partial columns (1013.25–345 hPa) are assimilated in a chemistry transport model to produce 6-hourly analyses of tropospheric ozone for 6 years (2008–2013). We have compared and evaluated the IASI-MLS analysis and the MLS analysis to assess the added value of IASI measurements. <br><br> The global chemical transport model MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle) has been used with a linear ozone chemistry scheme and meteorological forcing fields from ERA-Interim (ECMWF global reanalysis) with a horizontal resolution of 2° × 2° and 60 vertical levels. The MLS and IASI O<sub>3</sub> retrievals have been assimilated with a 4-D variational algorithm to constrain stratospheric and tropospheric ozone respectively. The ozone analyses are validated against ozone soundings and tropospheric column ozone (TCO) from the OMI-MLS residual method. In addition, an Ozone ENSO Index (OEI) is computed from the analysis to validate the TCO variability during the ENSO events. <br><br> We show that the assimilation of IASI reproduces the variability of tropospheric ozone well during the period under study. The variability deduced from the IASI-MLS analysis and the OMI-MLS measurements are similar for the period of study. The IASI-MLS analysis can reproduce the extreme oscillation of tropospheric ozone caused by ENSO events over the tropical Pacific Ocean, although a correction is required to reduce a constant bias present in the IASI-MLS analysis.https://www.atmos-chem-phys.net/18/6939/2018/acp-18-6939-2018.pdf |
| spellingShingle | H. Peiro E. Emili D. Cariolle D. Cariolle B. Barret E. Le Flochmoën Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO Atmospheric Chemistry and Physics |
| title | Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO |
| title_full | Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO |
| title_fullStr | Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO |
| title_full_unstemmed | Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO |
| title_short | Multi-year assimilation of IASI and MLS ozone retrievals: variability of tropospheric ozone over the tropics in response to ENSO |
| title_sort | multi year assimilation of iasi and mls ozone retrievals variability of tropospheric ozone over the tropics in response to enso |
| url | https://www.atmos-chem-phys.net/18/6939/2018/acp-18-6939-2018.pdf |
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