Based on automatic continuous surface ozone concentration observation data from June 10, 2010 to March 20, 2012 in the Taklimakan Desert hinterland, combined with corresponding meteorological data, the temporal, seasonal and daily variation characteristics of surface ozone concentrations under different weather conditions were analyzed. At the same time, the main fac- tors affecting ozone variation are discussed. Results show that： （1） Daily variation of ozone concentration was characterized by one obvious peak, with gentle changes during the night and dramatic changes during the day. The lowest concentration was at 09：00 and the highest was at 18：00. Compared to urban areas, there was a slight time delay. （2） Ozone concentration variation had a weekend effect phenomenon. Weekly variation of ozone concentration decreased from Monday to Wednesday with the lowest in Wednesday, and increased after Thursday with the highest in Sunday. （3） The highest monthly average concentration was 89.6 I.tg/m3 in June 2010, and the lowest was 32.0 ~g/m3 in January 2012. Ozone concentration reduced month by month from June to December in 2010. （4） Ozone concentration in spring and summer was higher than in autumn and winter. The variation trend agreed with those in other large and medium-sized cities. （5） Under four different types of weather, daily ozone concentration var- ied most dramatically in sunny days, followed by slight variation in rain days, and varied gently in cloudy days. Ozone concentra- tion varied inconspicuously before a sandstorm appearance, and dropped rapidly at the onset of a sandstorm. （6） Daily variation of radiation was also characterized by a single peak, and the variation was significantly earlier than ozone concentration variation. Sun radiation intensity had a direct influence on the photochemical reaction speed, leading to variation of ozone concentration. （7） Daily average ozone concentration in dust weather was higher than in slight rain and clear days. The variation
XinChun LiuYuTing ZhongQing HeYanMei PengXingHua YangAli MamtiminWen Huo
During the course of a major sandstorm from April 17 to April 23, 2008 in the Taklimakan Desert, data pertaining to the mass concentrations of different-sized atmospheric particulate matter were observed continuously with Grimm 1.108, Thermo RP 1400a, TSP, and CAWS-600 instruments. The results showed that： （1） during the entire sandstorm process there were some dif- ferences between the daily mean particle concentration peaks and the hourly mean particle concentration peaks because the actual sandstorm lasted for only about 4 hr, whereas more particles were accumulated in the floating dust days before and after the actual sandstorm; （2） the intensity of the sandstorm was enhanced with the increase of wind speed, and this was related to the peak mass concentrations of atmospheric particulate matter; the wind speed directly affected the concentration of atmospheric particulate matter： the higher the wind speed, the higher the mass concentration （〉0.23 μm was 39,496.5 μg/m^3, and 〉20.0 μm was 5,390.7μg/m^3）; （3） the concentration changes of PM10 and TSP were also related to the course and intensity of the sandstorm; and （4） the mass concentration of atmospheric particulate matter had the following sequence during the dust weather： clear day 〈 floating dust 〈 floating and blowing dust 〈 sandstorm. Temperature, relative humidity, and barometric pressure are important factors affecting the strength of storms, which could also indirectly affect the concentration change of atmospheric particulate matter.
XinChun LiuYuTing ZhongQing HeXingHua YangAli MamtiminWen Huo
