The objective of this work is to better understand freezing
fog/drizzle conditions using observations collected during the Fog
Remote Sensing and Modeling project (FRAM-S) that took place at St.
John's International Airport, St. John's, NL, Canada. This
location was ~1 km away from the Atlantic Ocean coast. During the
project, the following measurements at one minute resolution were
collected: precipitation rate (PR) and amount, fog/drizzle
microphysics, 3D wind speed (Uh) and turbulence (Uh'),
visibility (Vis), IR and SW radiative fluxes, temperature (T) and
relative humidity (RH), and aerosol observations. The reflectivity
and microphysical parameters obtained from the Metek Inc. MRR
(Microwave Rain Radar) were also used in the analysis. The
measurements were then used to obtain freezing fog/drizzle
microphysical characteristics and their relation to visibility.
The ground-based CIP (Cloud Imaging Probe) measurements of
freezing fog/drizzle particles together with hydrometeor
measurements obtained from disdrometers have been used in the
analysis. During FRAM-S, ice accumulation over the surfaces was
more than 2 cm on 26 March 2009 and this affected some of the
various sensors but the major instruments worked properly to get
freezing fog/drizzle conditions. The results suggested that better
prediction techniques for freezing fog/drizzle events are needed
for marine environment applications. Particle microphysical
measurements play a crucial role for developing better
nowcasting/forecasting techniques.