Abstract:By means of wind, temperature, relative humidity, visibility, and PM10 mass concentration data from the 20 m observing tower, three sand and dust storm (SDS) events observed at Datong from March 2009 to March 2010 are studied in the aspects of the variation characteristics of near surface meteorological parameters and PM10These three sand and dust storm events (i.e., dust storm, blowing sand, and floating dust) are corresponding to three typical the sand and dust weather processes.The observation data show that the wind speeds during a dust storm and blowing sand were stronger than that during floating dust.The vertical gradients of wind speeds at 1, 2, 4, 10, 20 m heights during local blowing sand cases (with the wind speed ratios being greater that of 20 m, from 041 to 079) were stronger than those in other two cases (with the wind speed ratios being greater that of 20 m, from 048 to 084).Anomalous near surface temperature variability was observed during the floating dust event, reflecting the impact of dust aerosol radiative forcing on near surface air temperature. Also, anomalous non relevant changes between relative humidity and air temperature were observed during the dust storm event, reflecting the possible impact of the dry air mass from desert regions.The averaged PM10 mass concentration levels during three sand and dust storm events were several fold higher than those during non SDS periods, and the PM10 concentration levels were: dust storm > blowing sand > floating dust.The variation of PM10 mass concentration is not solely relevant with wind speeds. In the late period of SDS events, because fine particles were blowing continuously out of the near surface air, PM10 mass concentration shows non synchronous decrease with visibility and wind speeds.
