Validation of Ozone Monitoring Instrument (OMI) ozone profiles and stratospheric ozone columns with Microwave Limb Sounder (MLS) measurements

摘要

We validate OMI ozone profiles between 0.22–215 hPa and stratospheric ozonecolumns down to 215 hPa (SOC215) against v2.2 MLS data from 2006. Thevalidation demonstrates convincingly that SOC can be derived accurately fromOMI data alone, with errors comparable to or smaller than those from currentMLS retrievals, and it demonstrates implicitly that tropospheric ozonecolumn can be retrieved accurately from OMI or similar nadir-viewingultraviolet measurements alone. The global mean biases are within 2.5%above 100 hPa and 5–10% below 100 hPa; the standard deviations of thedifferences (1σ) are 3.5–5% between 1–50 hPa, 6–9% above 1 hPaand 8–15% below 50 hPa. OMI shows some latitude and solar zenith angledependent biases, but the mean biases are mostly within 5% and thestandard deviations are mostly within 2–5% except for low altitudes andhigh latitudes. The excellent agreement with MLS data shows that OMIretrievals can be used to augment the validation of MLS and otherstratospheric ozone measurements made with even higher vertical resolutionthan that for OMI. OMI SOC215 shows a small bias of −0.6% with astandard deviation of 2.8%. When compared as a function of latitude andsolar zenith angle, the mean biases are within 2% and the standarddeviations range from 2.1 to 3.4%. Assuming 2% precision for MLSSOC215, we deduce that the upper limits of random-noise and smoothing errorsfor OMI SOC215 range from 0.6% in the southern tropics to 2.8% atnorthern middle latitudes.