Improve the retrieval sensitivity to lower tropospheric ozone and long-term consistency of SAO OMI ozone profile retrieval

We have validated the Ozone Monitoring Instrument (OMI) ozone profile (PROFOZ) product from October 2004 through December 2014 retrieved by the Smithsonian Astrophysical Observatory (SAO) algorithm against ozonesonde and Microwave Limb Sounder (MLS) observations. The retrieval shows generally good agreement with ozonesonde and MLS observations especially in the tropics and mid-latitudes. The retrieval comparison demonstrates good long-term stability during the pre-row anomaly period (i.e., before the serious occurrence of row anomaly in January 2009), but exhibits statistically significant trend of 0.77 DU/year in SOC and -0.25 DU/year in TOC during the post-RA period as shown in Figure 1. We are updating our ozone profile retrieval algorithm to include the developed tropopause-based ozone profile climatology (Bak et al., 2013), recently developed cloud retrieval (Cai et al., 2016), and updated OMI slit functions. We will improve the retrieval sensitivity to lower tropospheric ozone using longer non-O3 absorbing wavelengths to reduce the interference from surface albedo and by improving the characterization of the OMI measurement error. We will also improve the long-term consistency of the retrieval by developing time-dependent soft calibration. Updated retrievals will be validated against ozonesonde observations.