Abstract:

Total dust aerosol emission is one of the most critical factors in the study of climate and environmental change. The dust emission mechanism of power-dominated dust storms can only explain the amount of dust aerosols during dust storms， but not the presence of large amounts of dust aerosols during non-dust storms， implying that there may be other dust emission mechanisms in addition to the dust storm emission mechanism. Using the 1-min high-resolution wind speed observation data of Tengger Desert in 2021， we calculate the dust emissions from gusts in a weak wind background and from dust storms in a strong wind background based on the generalized Gillette dust emission scheme. The results show that： （1） Gusts have obvious turbulence structure and randomness， and the frequency of wind speeds greater than the critical dust-raising speed accounts for about 8% of the total annual wind speeds， and the wind speed of 10-min and 1-h average is difficult to capture gusts dust emission in the context of weak winds. （2） Dust emission from dust storm is 5-100 times that of gusts， but the cumulative effect of gust should not be ignored， which is one of the main sources of dust aerosols in the atmospheric background. （3） The gust emissions are absolutely dominant in the non-dusty months， while the dust storm emissions are dominant in dusty months. In terms of the contribution to the total annual dust emissions， the contribution of dust storms is 45% while that of gusts is 55%， which suggests that the cumulative effect of dust emissions from gusts plays an important role in further refining the existing dust emission mechanism， and that the impacts of its huge amount of dust aerosols on the climate and environmental changes are in need of urgent reassessment.

Key words: gusty dust emission, dust aerosol, dust flux, dust storm, contribution rate