Comparison of Ozone Measurements by Satellite, Sondes, and Other Instruments over North America During the IONS (2006) Campaign

Open Access
- Author:
- Hui, Wan Ching Jacquie
- Graduate Program:
- Meteorology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 04, 2008
- Committee Members:
- Anne Mee Thompson, Thesis Advisor/Co-Advisor
Eugene Edmund Clothiaux, Thesis Advisor/Co-Advisor
Jerry Y Harrington, Thesis Advisor/Co-Advisor - Keywords:
- MLS
OMI
Aura
ozonesonde
ozone
shadowband radiometer - Abstract:
- The NASA Aura satellite houses four instruments to study atmospheric ozone. The Ozone Monitoring Instrument (OMI) onboard the satellite provides global total column ozone (TCO) and in combination with other instruments tropospheric ozone residual (TOR) can be derived. In this study, the trajectory-enhanced tropospheric ozone residual (TTOR) product of Schoeberl et al. [2007] is compared with ground-based observations and ozonesonde soundings to investigate the discrepancies between the observations on a day-to-day basis over Richland, Washington, and four other stations during the Intercontinental Transport Experiment-B (INTEX-B)/IONS-06 (INTEX Ozonesonde Network Study 2006)campaign. Discrepancies between sonde and OMI observations are examined with statistical and meteorological tools. Intercomparison of TCO obtained from different instruments in Richland shows high correlation but systematic differences due to inaccurate instrument calibrations. OMI TCO exhibits a persistent low bias relative to the sondes over 10 DU in Richland and two other mid-latitude stations in spring 2006. Days with low tropopause heights and overcast skies have significantly higher sonde-OMI discrepancies in Richland. Clear seasonal and geographical variations in the distribution of TOR differences are observed, but the underlying reasons are unclear. Maps of tropospheric ozone and potential vorticity show higher uncertainty in TOR in regions with large Ertel's potential vorticity (EPV) gradients. An agglomerative hierarchical clustering is employed to categorize tropospheric ozone profiles to identify patterns that may cause differences in sonde and OMI-derived values of TOR. Clustering produced outliers of ozone profiles that represented special meteorological conditions, such as tropopause folds or presence of thick ozone-rich layers in the profiles, but offered few insights into the sonde-OMI disagreements. An extension of the study to other sites and seasons will allow us to make more robust analyses in sonde-OMI comparisons.