Climatological characteristics of the low#x2010;level tropospheric temperature inversion in the Canadian Arctic are examined using 10#x2013;40 year records of upper#x2010;air meteorological data. Inversions at the northern sites are primarily surface#x2010;based in winter, and elevated from mid#x2010;spring through summer. At the southern sites, a bimodal pattern is observed with surface#x2010;based inversions occurring during late summer, as well as during winter. From comparisons of our results with other published climatologies, it appears that this bimodal pattern reflects interactions between short#x2010; and long#x2010;wave radiation, synoptic activity and snowmelt. Maxima in inversion depth and temperature difference across the inversion layer occur in February and March; minima occur in August and September. The annual progression of inversion characteristics closely follows the annual pattern of clear#x2010;sky percentages, reflecting the controlling influence of cloud and clear#x2010;sky radiative forcings on the inversion layer.
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