Ice Fog in Arctic During FRAM–Ice Fog Project: Aviation and Nowcasting Applications

Abstract

Ice fog and frost occur commonly (at least 26% of the time) in the northern latitudes and Arctic regions during winter at temperatures usually less than about –15°C. Ice fog is strongly related to frost formation—a major aviation hazard in the northern latitudes. In fact, it may be considered a more dangerous event than snow because of the stronger aircraft surface adhesion compared to snow particles. In the winter of 2010/11, the Fog Remote Sensing and Modeling–Ice Fog (FRAM-IF) project was organized near Yellowknife International Airport, Northwest Territories, Canada, with the main goals of advancing understanding of ice fog microphysical and visibility characteristics, and improving its prediction using forecast models and remotesensing retrievals. Approximately 40 different sensors were used to measure visibility, precipitation, ice particle spectra, vertical thermodynamic profiles, and ceiling height. Fog coverage and visibility parameters were estimated using both Geostationary Operational Environmental Satellites (GOES) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. During this project, the inversion layer usually was below a height of 1.5 km. High humidity typically was close to the ground, frequently producing ice fog, frost, and light snow precipitation. At low temperatures, snow crystals can be swept away by a very low wind speed (∼1 m s−1). Ice fog during the project was not predicted by any forecast model. These preliminary results in the northern latitudes suggest that ice fog and frost studies, over the Arctic regions, can help us to better understand ice microphysical processes such as ice nucleation, visibility, and parameterizations of ice fog.

Genesis of diamond dust, ice fog and thick cloud episodes observed and modelled above Dome C, Antarctica

“…McMurdo in Lazzara (2010). Based on Gultepe et al (2014) and Arctic studies, the maximum size for ice fog crystals is about 200 µm with diamond dust ice crystal sizes greater than 200 µm. In the East Antarctic Plateau over all the seasons except summer, a strong surface-based temperature inversion persists in which small ice crystals referred to as diamond dust/ice fog form in the boundary layer (Walden et al, 2003).…”

Introduction Ice Fog, Ice Clouds, and Remote Sensing

“…2016;Gultepe et al 2014Gultepe et al , 2015. Aircraft-produced ice particles (APIPs) in supercooled cloud conditions can be seen over the airports or behind aircraft (Heymsfield et al 2011;Woodley et al 1991;Langmuir et al 1948;Ludlam 1956).…”

Ice Fog and Light Snow Measurements Using a High-Resolution Camera System

“…In their Alaska field study, Schmitt et al (2013) found that for temperatures colder than -30°C, most particles are below 30 lm in size with concentrations generally increasing from very low values at 100 lm to a maximum at about 10 lm. Gultepe et al (2014) used GCIP, a ground-based version of the aircraft CIP optical array probe (Baumgardner et al 2001) for ice fog studies. The shape measurements of ice crystals from GCIP were limited by its poorer resolution (pixel resolution of 15 lm) showing the need for a better probe to detect size, shape, and size distributions of ice crystals.…”

“…The overall goals of this work are to contribute to a better characterization of ice fog particle microphysical properties as well as small snow crystal properties for modelling and observational studies. Observations, representing ice fog and light snow crystals, were carried out during the FRAM project (fog remote sensing and modeling), which took place over Yellowknife International Airport, NWT, Canada during winter of 2010-2011 (Gultepe et al 2014(Gultepe et al , 2015b, and are used in achieving the goals. For accomplishing this work, the following objectives are considered: (1) present a ground-based instrument, called the ice crystal imaging (ICI) probe that provides size, shape, and fall speed of small ice particles; (2) show the capability of ice crystal fallspeed (V f ) measurement using ICI probe; (3) derive microphysical characteristics of small ice crystals applicable to cloud-climate studies; and (4) compare the results with other studies to validate accuracy of present measurements.…”