Near-real time retrieval of tropospheric NO 2 from OMI

作者：K. F. Boersma, Henk Eskes, Pepijn Veefkind, E. J. Brinksma, R. J. van der A, Maarten Sneep, G. H. J. van der Oord, P. F. Levelt, P. Stammes, J. F. Gleason, E. J. Bucsela · 发表于：Atmospheric chemistry and physics · 年份：2007 · DOI：10.5194/acp-7-2103-2007 · 被引用次数：370 · 研究领域：Atmospheric Ozone and Climate、Atmospheric chemistry and aerosols、Atmospheric and Environmental Gas Dynamics

Abstract. We present a new algorithm for the near-real time retrieval – within 3 h of the actual satellite measurement – of tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI). The retrieval is based on the combined retrieval-assimilation-modelling approach developed at KNMI for off-line tropospheric NO2 from the GOME and SCIAMACHY satellite instruments. We have adapted the off-line system such that the required a priori information – profile shapes and stratospheric background NO2 – is now immediately available upon arrival (within 80 min of observation) of the OMI NO2 slant columns and cloud data at KNMI. Slant columns for NO2 are retrieved using differential optical absorption spectroscopy (DOAS) in the 405–465 nm range. Cloud fraction and cloud pressure are provided by a new cloud retrieval algorithm that uses the absorption of the O2-O2 collision complex near 477 nm. On-line availability of stratospheric slant columns and NO2 profiles is achieved by running the TM4 chemistry transport model (CTM) forward in time based on forecast ECMWF meteo and assimilated NO2 information from all previously observed orbits. OMI NO2 slant columns, after correction for spurious across-track variability, show a random error for individual pixels of approximately 0.7×1015 molec cm−2. Cloud parameters from OMI's O2-O2 algorithm have similar frequency distributions as retrieved from SCIAMACHY's Fast Retrieval Scheme for Cloud Observables (FRESCO) for August 2006. On average, ...