Examining Summer Fog Properties in Halifax, Nova Scotia

Abstract:

Fog is a well-known meteorological hazard in Maritime Canada, but its physical properties are challenging to quantify. We conducted the Halifax Fog and Air Quality Study (HaliFAQS) during May-August 2019 to examine fog events in Halifax, Nova Scotia. Fog droplet data were collected with a Fog Monitor (FM-120, Droplet Measurement Technologies), and wind data were collected with an Airpointer. These datasets were processed together to apply correction factors to the fog droplet data (based on Spiegel et al., 2012) and to examine correlations between the two datasets. Our primary focus will be on the variations or trends in the liquid water content, droplet sizes, and cloud droplet number concentrations present during the fog events. We are interested in variations both during individual fog events and between the different events over the course of the season. These microphysical fog properties can have important impacts on visibility as well as radiative impacts determining how much the cloud warms or cools the atmosphere relative to a clear sky. Characterizing droplet properties can allow us improve model visibility parameterizations. Finally, these observations and analyses can be included with other nearby studies for trend analysis of fog climatology over longer periods of time. As such, we can better characterize the properties of summer fogs in Maritime Canada.