SCIAMACHY data from January 2003 to December 2005 (available at TEMIS
project website, www.temis.nl) were used in the present study. SCIAMACHY is
onboard the ENVISAT satellite and was launched in February 2002 (Cortesi et al
2007). Since then it has measured NO2(wavelengths of 425–450 nm; see Richter et al.
2005) and a number of other trace gases. ENVISAT flies in a sun-synchronous orbit.
It crosses the equator at 10 am in descending mode and covers the globe in six days.
Resolution of SCIAMACHY is approximately 30 km along-track (north–south) and
60 km cross-track (east–west). More details on the retrieval are discussed in Boersma
et al. (2004) and Van der A et al. (2006).