Satellite-based evidence of dust emission over Northern Canada

Abstract. High latitude dust (HLD) is receiving growing research interest as its relative impact in the Arctic has been elucidated. Precise knowledge of HLD emission locations is limited in both field studies and satellite observations, leading to a general lack of representation in global models. Using the Frequency of Occurrence (FoO) of above-average Dust Optical Depth (DOD > 0.5) from twenty years (2002–2022) of high-resolution MODIS observations derived for this study (0.1° x 0.1°), we present quantitative evidence that dust sources are widespread across the Canadian Arctic. Additionally, we present qualitative supporting evidence from aerosol type ‘dust’ classifications in VIIRS and CALIPSO satellite data products, as well as some challenges of comparing MODIS AOD to two co-located AERONET sites.

The HLD hotspots identified in the “Canadian Arctic Dust Belt” correspond to surfaces with high potential for dust emission in the G-SDS-SBM dataset. There are more areas where hotspots are observed but emission potential is low than the opposite case; additionally, two considerable areas of dust emission are identified at lower latitudes in mainland Canada. When spatially averaged across the broad dust producing region (65° N – 85° N, 125° W – 70° W), annual mean time series of FoO of MODIS DOD > 0.5 suggest an increase in the frequency of dustiness in the latter decade, consistent with our understanding that HLD emissions are increasing in a warming climate. These results further motivate model development to include HLD sources and provide an observational basis for evaluating them.