Performance of a low-cost optical particle counter (Alphasense OPC-N3) for estimating size-resolved dust emission flux using eddy covariance

Abstract. The recent development of low-cost optical particle counters (OPCs) presents new opportunities for improving spatial coverage of particle concentration in the atmosphere as they are more affordable, compact, and consume less power than traditional OPCs. In particular, these OPCs could improve our ability to quantify dust emissions in complex environments during aeolian soil erosion. The high frequency sampling capacity (1 Hz) of some sensors may make them suitable for estimating dust emissions using the eddy-covariance method. Here, the capability of the low-cost OPC-N3 from Alfasense to estimate the size-resolved dust flux using the eddy-covariance method is evaluated. During the Jordan Wind Erosion and Dust Investigation (J-WADI) experiment, we tested one OPC-N3 against traditional reference OPCs. The OPCs were located in close proximity to a sonic anemometer, enabling the correlation of dust concentration and vertical velocity fluctuations for estimating dust fluxes. Despite the high temperature and dusty wind conditions of the campaign, the N3 monitored the dynamics and magnitude of dust concentration with reasonable precision. The turbulence characteristics of the dust concentration fluctuations measured by the N3 were similar to those from the reference OPC. After calibrating the N3 dust concentration, the N3 accurately estimated the dust emission flux, with differences of less than 30 % compared to the reference OPC. Our results confirm the potential of low-cost OPCs for dust-erosion research. Nonetheless, further evaluation of low-cost OPCs is still needed across different environments and weather conditions.