Research Article
Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China
Figure 6
Average tropospheric FNR in JJA for 2005–2016. (a) 2005, (b) 2006, (c) 2007, (d) 2008, (e) 2009, (f) 2010, (g) 2011, (h) 2012, (i) 2013, (j) 2014, (k) 2015, and (l) 2016. FNR is defined as the ratio of tropospheric HCHO column concentration to tropospheric NO2 column concentration.