Horizontal and vertical fluxes of particulate matter during wind erosion on arable land in the province La Pampa, Argentina

SIEGMUND NICOLE; FUNK ROGER; SOMMER MICHAEL; AVECILLA FERNANDO; PANEBIANCO ESTEBAN; ITURRI ANTONELA; BUSCHIAZZO DANIEL

Simposio; Blowing South: Southern Hemisphere Dust Symposium; 2021

A detailed analysis of horizontal and vertical PM fluxes during wind erosion has been conducted, based on measurements of PM10, PM2.5 and PM1.0 concentrations at windward and leeward positions on a measuring field. The three fractions of PM are differently influenced by the increasing wind and shear velocities of the wind. The measured concentrations of the coarser fractions of the fine dust, PM10 and PM2.5, increase with wind and shear velocity, whereas PM1.0 concentrations show no clear correlation to 14 the shear velocity. The share of PM2.5 on PM10 is depending on the measuring height and wind speed and varies between 4 to 12 m s-1 in 1 m height ranging from 25 to 7 % (average 10%), and in 4 m height from 39 to 23 % (average 30%). Although general relationships between wind speed, PM concentration, and horizontal and vertical fluxes could be found, the contribution of the measuring field was very low, as balances of incoming and outgoing fluxes show. Consequently, the measured PM concentrations are determined by a variety of sources, as traffic on unpaved roads, cattle drives, tillage operations and wind erosion, and thus representing all components of land use and landscape structure in the near and far surroundings of the measuring field. Our results may rather reflect factors from the landscape scale thanbeing influenced by field-related variables. The used measuring devices to monitor PM concentrations showed differences of up to 20%, which led to considerable deviations when determining total balances. Differences up to 67% between the calculated fluxes prove the necessity of a previous calibration of the used devices.