SIZE RESOLVED DUST EMISSION FLUXES MEASURED BY THE GRADIENT METHOD DURING 6 DUST STORMS OF THE WIND-O-V's 2017 EXPERIMENT IN SOUTHERN TUNISIA

International audienceDust size distribution is a critical parameter to understand the interactions of mineral dust with its environment throughoutits life cycle [1]. This is why it is important to document this characteristic of mineral dust from emission to deposition,included the atmospheric transport phase. Until recently, because of the limitation of the available instrumentation, onlythe total dust mass flux could be measured at emission, and this with a limited (half hourly at best) temporal resolution.The development of optical particle counters has allowed overcoming this limitation and the dust size distributions cannow be measured at high frequency.Using a dedicated experimental setup, size resolved dust emission fluxes were documented on a bare plot in southernTunisia in the framework of the first intensive observing period of the WIND-O-V (WIND erOsion in presence ofVegetation) program (grant ANR-15-CE02-0013). The experiment was conducted from 1 March to 15 May 2017 in theDar Dhaoui Experimental Range of the Institut des Régions Arides of Médenine. Size resolved dust emission fluxes werecomputed using the gradient method [2] and using for the first time WELAS optical particle counters.During the field campaign, 6 dust storms were sampled. In the present work, the size resolved dust emission fluxesmeasured during the dust storms are presented and discussed in relation with the meteorological characteristics of thestorms and the characteristics of the soil surface