Near-real time retrieval of tropospheric NO<sub>2</sub> from OMI

Abstract

Abstract. We present a new algorithm for the near-real time retrieval -within 3 h of the actual satellite measurement -of tropospheric NO 2 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 NO 2 from the GOME and SCIAMACHY satellite instruments. We have adapted the off-line system such that the required a priori informationprofile shapes and stratospheric background NO 2 -is now immediately available upon arrival (within 80 min of observation) of the OMI NO 2 slant columns and cloud data at KNMI. Slant columns for NO 2 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 O 2 -O 2 collision complex near 477 nm. Online availability of stratospheric slant columns and NO 2 profiles is achieved by running the TM4 chemistry transport model (CTM) forward in time based on forecast ECMWF meteo and assimilated NO 2 information from all previously observed orbits. OMI NO 2 slant columns, after correction for spurious across-track variability, show a random error for individual pixels of approximately 0.7×10 15

NO<sub>2</sub> measurements in Hong Kong using LED based long path differential optical absorption spectroscopy

“…It is on board the Earth Observing System's (EOS) Aura satellite which was launched on 15 July 2004 and is collecting data since 9 August 2004, providing more than 6 yr of daily global NO 2 maps (Boersma et al, 2007). The Aura satellite orbits at an altitude of 705 km are in a sun-synchronous polar orbit with an exact 16 day repeat cycle and a local equator crossing time of 13:45 LT (local time) on the ascending node.…”

Intercomparison of SCIAMACHY and OMI tropospheric NO2 columns: Observing the diurnal evolution of chemistry and emissions from space

“…For SCIAMACHY retrievals, which have a better fitting precision, the base component is 0.3-1.0 Â 10 15 molecules cm À2 . Following Boersma et al [2007], we adopt a relative (AMF) component of $30%, so that the total error for individual retrievals is approximated by 0.65 Â 10 15 + 0.3 Â N v (SCIAMACHY) and 1.0 Â 10 15 molecules cm À2 + 0.3 Â N v (OMI).…”

“…This variability is significantly reduced, but not removed altogether, by the correction procedure described by Boersma et al [2007]. Any residual error that remains after the correction procedure is an implicit part of the OMI slant column error estimate of 0.7 Â 10 15 molecules cm À2 that we use in the remainder of the manuscript.…”

“…The estimate of stratospheric NO 2 thus adjusts to observed NO 2 over regions dominated by stratospheric NO 2 (e.g., oceans), while stratospheric winds in TM4 ensure the propagation of the assimilated information. See Boersma et al [2007] for more details.…”

Analysis of NO2over the Korean Peninsula from Ozone Monitoring Instrument Satellite Measurements

“…그리고 이산화질소에 노출되어 흡입할 경우 폐질환을 일으 킬 수 있으며 (Cheon et al, 2010) (Han et al, 2011;Wang et al, 2011;Sheel et al, 2010;Chai et al, 2009;Kurokawa et al, 2009;Zyrichidou et al, 2009;Shi et al, 2008;He et al, 2007;Ma et al, 2006), 위성자료와 지상관측 자료 또는 항 공기 관측 자료와의 상호 비교 분석 (Gruzdev and Elokhov, 2010;Lamsal et al, 2010Lamsal et al, , 2008Ionov et al, 2008Ionov et al, , 2006, 위성 간의 상호 비교 분석 Bracher et al, 2005 (Han et al, 2011;Hains et al, 2010; Boersma et al, 2007 3. 2 지상관측 NO 2 농도 변화 경향 참 고 문 헌…”