Monthly averages of the tropospheric vertical columns of nitrogen dioxide over East Central China, as measured by GOME and SCIAMACHY from 1996 to 2004. GOME is represented by open symbols and SCIAMACHY data by closed symbols.
A plot of the monthly mean of the three-day composite of the tropospheric nitrogen dioxide vertical column versus time is presented for the area. SCIAMACHY nadir measurements started in August 2002 but limited data are currently available prior to February 2003. The shaded areas represent the standard deviation estimated for the monthly mean three-day composite, taking into account the variability of the measurements and data gaps.