Impacts Of Sand Weathers And Dust Devils On The Local Dust Emission Amount

Sand and dust account for more than half of atmospheric aerosols.It not only affects the climate,but also affects the quality of atmospheric environment.The aerodynamic equivalent diameter greater than 10 u m solid particles naturally fall on the ground is the amount of dust,which is more than the TSP,PM and other indicators can reflect the entire layer of dust information.Dust and sandstorms driven by dust are considered to be the most important source of dust aerosols.However,there is currently a widespread problem that simulated dust fluxes are much lower than observed values,indicating that there is a huge amount of dust aerosols missing.The thermal sand emission and dynamic sand emission were complement each other affected the content of dust aerosol over the desert area,which inevitably affects the change of dustfall.In this paper,the dust emission rate of sand and dust devils are estimated by WRF/Chem sand-dust storm model and the amount of sand weather to the dust emission and dust devils emission are analyzed.The relationship between them and natural dustfall is analyzed,and their respective contributions to the total dust content of the atmosphere are given.The research can be concluded as following:1)The semi-quantitative dust weather days have a highly significant positive correlation with monthly dustfall,and the relevant degrees of gale days>floating days>dust storm days>blowing sand days,but only with half the sand days quantitative indicators to quantify the amount of dustfall are not enough to quantify the source of dustfall more precisely;2)The dust emission from sandstorms calculated by the WRF/Chem sandstorm model is roughly the same as the change in dustfall,and it is responsible for the total the average contribution rate of sand is 76%,but the dust weather only reflects the source of some atmospheric deposition,and it cannot explain the phenomenon that dust is not generated but the dustfall is still high;3)In order to get the dust devils amounts,the maximum convective boundary layer thickness was calculated,and the maximum convective boundary layer thickness results showed significant annual variations.Both were in the trough from December to January,and reached the crest in June of the year.The interannual variation was relatively flat.And studies have found that the influence of thermal and dynamic factors on CBLmax is significant,and the amount of cloudiness can affect the variation of CBLmax.4)The amount of dust generated by dust devils shows a typical annual single-peak change,with the largest in summer and the lowest in winter.The average annual sediment discharge is 57.09t/km2.Its contribution to the total sediment yield has reached 24%,especially in the absence of sand.Respectively,the contribution of dust devils is 24%.When there is no sand weather,dust devil is the only source of the dustfall.The total dust emission and dustfall caused by dust weather and dust winds have extremely significant positive correlations in the monthly and annual changes,which both passed the significance test (P<0.001).