Evaluation of tropospheric ozone columns derived from assimilated GOME ozone profile observations
Item
Title (Dublin Core)
Evaluation of tropospheric ozone columns derived from assimilated GOME ozone profile observations
Description (Dublin Core)
Tropospheric O<sub>3</sub> column estimates are produced and evaluated from spaceborne O<sub>3</sub> observations by the subtraction of assimilated O<sub>3</sub> profile observations from total column observations, the so-called Tropospheric O<sub>3</sub> ReAnalysis or TORA method. Here we apply the TORA method to six years (1996–2001) of ERS-2 GOME/TOMS total O<sub>3</sub> and ERS-2 GOME O<sub>3</sub> profile observations using the TM5 global chemistry-transport model with a linearized O<sub>3</sub> photochemistry parameterization scheme. <br><br> Free running TM5 simulations show good agreement with O<sub>3</sub> sonde observations in the upper-tropospheric and lower stratospheric region (UTLS), both for short day-to-day variability as well as for monthly means. The assimilation of GOME O<sub>3</sub> profile observations counteracts the mid-latitude stratospheric O<sub>3</sub> drift caused by the overstrong stratospheric meridional circulation in TM5. Assimilation of GOME O<sub>3</sub> profile observations also improves the bias and correlations in the tropical UTLS region but slightly degrades the model-to-sonde correlations and bias of extra-tropical UTLS. We suggest that this degradation is related to the large ground pixel size of the GOME O<sub>3</sub> measurements (960×100 km) in combination with retrieval and calibration errors. The added value of the assimilation of GOME O<sub>3</sub> profiles compared to stand-alone model simulations lays in the long term variations of stratospheric O<sub>3</sub>, not in short term synoptic variations. <br><br> The evaluation of daily and monthly tropospheric O<sub>3</sub> columns obtained from total column observations and using the TORA methodology shows that the use of GOME UV-VIS nadir O<sub>3</sub> profiles in combination with the spatial resolution of the model does not result in satisfactory residual tropospheric ozone columns.
Creator (Dublin Core)
Laat, A. T. J.
der A, R. J.
Weele, M.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-9-8105-2009
https://acp.copernicus.org/articles/9/8105/2009/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
