Local dust plume analysis and classification using ground-based remote sensing and microphysical measurement acquired at Lhù’ààn Mân’ (Kluane Lake), Yukon

Abstract

The sub-Arctic Lhù’ààn Mân’ (Kluane Lake) region in the Canadian Yukon is subject to regular drainage wind-induced dust plumes emanating from the Slims River basin. This dust emissions site is just one of many current and potential future proglacial dust sources in the Canadian North. We employed ground-based passive and active remote sensing (RS) techniques to analyze the complementarity and redundancy of such RS retrievals relative to springtime (May 2019) Kluane Lake microphysical measurements. This included correlation analyses between ground-based coarse mode (CM) aerosol optical depth (AOD) retrievals from AERONET AOD spectra, CM AODs derived from co-located Doppler lidar profiles and OPS (Optical Particle Sizer) surface measurements of CM particle-volume concentration ( ). An automated dust classification scheme tied to intercorrelations between lidar-derived CM AOD, AERONET-derived CM AODs and  variations was developed to objectively identify local dust events. Lidar ratios derived from a priori refractive indices and OPS-derived effective radius statistics were also validated using AERONET-derived CM AODs. Bi-modal CM PSDs from AERONET inversions showed CM peaks at ~ 1.3 µm and 5 – 6.6 µm radius: we argued that this was associated with springtime Asian dust and Lhù’ààn Mân’ dust, respectively. Correlations between the CIMEL-derived fine-mode (FM) AOD and FM OPS-derived particle-volume concentration suggest that remote sensing techniques can be employed to monitor FM dust (which is arguably a better indicator of the long-distance transport of HLD).