The measurements were carried out on Oct. 17–24, 2012, Jan. 17–24, April 9–16 and July 8–14, 2013 in five cities. While the observation was conducted on April 10–19, 2013 in spring and July 8–18, 2013 in summer of Nanjing, April 9–18, 2013 in spring of Suzhou, and July 8–12, 2013 in summer of Ningbo. Besides, some of the observation data were invalid on Oct. 17–24, 2012 in Ningbo and Oct. 21–24, 2012 in Hangzhou due to the man-made mistakes.