Near-real time retrieval of tropospheric NO 2 from OMI

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 system 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 ndash; profile shapes and stratospheric background NO2 ndash; is now immediately available upon arrival of the OMI NO2 slant columns and cloud data at KNMI. Slant column NO2 and cloud information arrives at KNMI typically within 80 min of actual OMI observations. 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 0.7×1015molec.cm?2. As NO2 retrievals are very sensitive to clouds, we evaluated the consistency of cloud fraction and cloud pressure from the new O2?O2 (OMI) algorithm and from the Fast Retrieval Scheme for Cloud Observables (FRESCO). Cloud parameters from the O2?O2 (OMI) algorithm have similar frequency distributions as cloud parameters retrieved from FRESCO (SCIAMACHY) for August 2006. On average, OMI cloud fractions are higher by 0.011, and OMI cloud pressures exceed FRESCO cloud pressures by 60 hPa. As a consistency check, we intercompared OMI near-real time NO2 columns measured at 13:45 h local time to SCIAMACHY off-line NO2 columns measured at 10:00 h local time. In August 2006, both instruments observe very similar spatial patterns of tropospheric NO2 columns, and small differences for most locations on Earth where tropospheric NO2 columns are small. For regions that are strongly polluted, SCIAMACHY observes higher tropospheric NO2 columns than OMI.

[1]  P. Levelt,et al.  Ground-based zenith sky abundances and in situ gas cross sections for ozone and nitrogen dioxide with the Earth Observing System Aura Ozone Monitoring Instrument. , 2005, Applied optics.

[2]  J. Hovenier,et al.  Global distributions of effective cloud fraction and cloud top pressure derived from oxygen A band spectra measured by the Global Ozone Monitoring Experiment: Comparison to ISCCP data , 2002 .

[3]  Pieternel F. Levelt,et al.  OMI level 0 to 1b processing and operational aspects , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[4]  Kelly Chance,et al.  Preliminary results for HCHO and BrO from the EOS-Aura Ozone Monitoring Instrument , 2004, SPIE Asia-Pacific Remote Sensing.

[5]  A. Stohl,et al.  Estimating the NO x produced by lightning from GOME and NLDN data: a case study in the Gulf of Mexico , 2005 .

[6]  J. Staehelin,et al.  SCIAMACHY tropospheric NO 2 over the Alpine region and importance of pixel surface pressure for the column retrieval , 2007 .

[7]  Daniele Bortoli,et al.  First comparison between ground-based and satellite-borne measurements of tropospheric nitrogen dioxide in the Po basin , 2004 .

[8]  A. Segers,et al.  On the use of mass-conserving wind fields in chemistry-transport models , 2002 .

[9]  Jay R. Herman,et al.  Earth surface reflectivity climatology at 340–380 nm from TOMS data , 1997 .

[10]  Henk Eskes,et al.  Intercomparison of SCIAMACHY nitrogen dioxide observations, in situ measurements and air quality modeling results over Western Europe , 2007 .

[11]  Ann Carine Vandaele,et al.  Measurements of the NO2 absorption cross-section from 42 000 cm−1 to 10 000 cm−1 (238–1000 nm) at 220 K and 294 K , 1998 .

[12]  R. Vautard,et al.  Comparison and evaluation of modelled and GOME measurement derived tropospheric NO 2 columns over Western and Eastern Europe , 2004 .

[13]  Michael Eisinger,et al.  Refinement of a Database of Spectral Surface Reflectivity in the Range 335-772 nm Derived from 5.5 Years of GOME Observations , 2003 .

[14]  Bernd Jähne,et al.  Quantitative analysis of NO x emissions from Global Ozone Monitoring Experiment satellite image sequences , 2001 .

[15]  M. Buchwitz,et al.  SCIAMACHY: Mission Objectives and Measurement Modes , 1999 .

[16]  Heikki Saari,et al.  The ozone monitoring instrument , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[17]  J. Burrows,et al.  Comparison of model-simulated tropospheric NO2 over China with GOME-satellite data , 2006 .

[18]  Lars Peter Riishojgaard,et al.  A direct way of specifying flow‐dependent background error correlations for meteorological analysis systems , 1998 .

[19]  Piet Stammes,et al.  Cloud pressure retrieval using the O2‐O2 absorption band at 477 nm , 2004 .

[20]  Juan Ramon Acarreta,et al.  Calibration comparison between SCIAMACHY and MERIS onboard ENVISAT , 2005, IEEE Geoscience and Remote Sensing Letters.

[21]  Alan Fried,et al.  Evaluation of GOME satellite measurements of tropospheric NO2 and HCHO using regional data from aircraft campaigns in the southeastern United States , 2004 .

[22]  N. Fournier,et al.  Improving cloud information over deserts from SCIAMACHY Oxygen A-band measurements , 2006 .

[23]  Aaron L. Swanson,et al.  Evaluation of space‐based constraints on global nitrogen oxide emissions with regional aircraft measurements over and downwind of eastern North America , 2006 .

[24]  Thomas P. Kurosu,et al.  Global inventory of nitrogen oxide emissions constrained by space‐based observations of NO2 columns , 2003 .

[25]  John P. Burrows,et al.  Comparison of 7 years of satellite‐borne and ground‐based tropospheric NO2 measurements around Milan, Italy , 2006 .

[26]  Thomas P. Kurosu,et al.  Satellite Mapping of Rain-Induced Nitric Oxide Emissions from Soils over Africa , 2004 .

[27]  Johannes W. Kaiser,et al.  Comparison of GOME tropospheric NO 2 columns with NO 2 profiles deduced from ground-based in situ measurements , 2006 .

[28]  Piet Stammes,et al.  Test and first validation of FRESCO+ , 2006, SPIE Remote Sensing.

[29]  Murry L. Salby,et al.  Diurnal Variations of Cloud Cover and Their Relationship to Climatological Conditions , 1996 .

[30]  Steffen Beirle,et al.  Retrieval and Analysis of Stratospheric NO2 from GOME , 2003 .

[31]  Bernd Jähne,et al.  Quantitative analysis of NOx emissions from GOME-satellite image sequences , 2001 .

[32]  John P. Burrows,et al.  Using GOME NO 2 satellite data to examine regional differences in TOMCAT model performance , 2004 .

[33]  J. Burrows,et al.  Measurements of nitrogen dioxide total column amounts using a Brewer double spectrophotometer in direct Sun mode , 2006 .

[34]  J. Hovenier,et al.  A fast method for retrieval of cloud parameters using oxygen A band measurements from the Global Ozone Monitoring Experiment , 2001 .

[35]  Klaus Pfeilsticker,et al.  Global tropospheric NO2 column distributions' Comparing three-dimensional model calculations with GOME , 2001 .

[36]  Glen Jaross,et al.  Ozone monitoring instrument calibration , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[37]  James F. Gleason,et al.  Algorithm for NO/sub 2/ vertical column retrieval from the ozone monitoring instrument , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[38]  Henk Eskes,et al.  Assimilation of GOME total‐ozone satellite observations in a three‐dimensional tracer‐transport model , 2003 .

[39]  J. Burrows,et al.  Tropospheric NO 2 columns: a comparison between model and retrieved data from GOME measurements , 2001 .

[40]  Steffen Beirle,et al.  NOx production by lightning estimated with GOME , 2004 .

[41]  Sander Houweling,et al.  The impact of nonmethane hydrocarbon compounds on tropospheric photochemistry , 1998 .

[42]  R. Martin,et al.  Multi-model ensemble simulations of tropospheric NO2 compared with GOME retrievals for the year 2000 , 2006 .

[43]  Henk Eskes,et al.  Averaging kernels for DOAS total-column satellite retrievals , 2003 .

[44]  John P. Burrows,et al.  First comparison of tropospheric NO2 column densities retrieved from GOME measurements and in situ aircraft profile measurements , 2002 .

[45]  Henk Eskes,et al.  Detection of the trend and seasonal variation in tropospheric NO2 over China , 2006 .

[46]  Kai Yang,et al.  Band residual difference algorithm for retrieval of SO/sub 2/ from the aura ozone monitoring instrument (OMI) , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[47]  Robert Voors,et al.  Method of calibration to correct for cloud-induced wavelength shifts in the Aura satellite's Ozone Monitoring Instrument. , 2006, Applied optics.

[48]  Henk Eskes,et al.  Error analysis for tropospheric NO2 retrieval from space , 2004 .

[49]  Steffen Beirle,et al.  Weekly cycle of NO 2 by GOME measurements: a signature of anthropogenic sources , 2003 .

[50]  Henk Eskes,et al.  Estimates of lightning NO x production from GOME satellite observations , 2005 .

[51]  Pawan K. Bhartia,et al.  Science objectives of the ozone monitoring instrument , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[52]  J. Burrows,et al.  Increase in tropospheric nitrogen dioxide over China observed from space , 2005, Nature.