Variation features of total atmospheric ozone in Beijing and Kunming based on Dobson and TOMS data

About 20 years of Dobson and TOMS data are used to analyze the variation characteristics of total atmospheric ozone in Beijing (39.93°N, 116.40°E) and Kunming (25.02°N, 102.68°E). It is shown that: (1) the long-term change trends for 1979 (or 1980)–2000 period are −0.642 DU/year and −0.009 DU/year respectively in Beijing and Kunming, (2) there are strong intra-seasonal variations especially in wintertime, which are comparable to seasonal variations both in Beijing and Kunming, (3) the long-term trend deduced from shorter time period of record is significantly different from that for longer time period, both in Kunming and Beijing, (4) there are significant QBO signals both in Beijing (mid latitude) and Kunming (low latitude), (5) the inter-annual variations of atmospheric ozone in both stations are mainly composed of the long-term trend and QBO signals, and (6) our Dobson and TOMS measurements of total ozone are generally in good agreement.