Representative values of icing-related variables aloft in freezing rain and freezing drizzle

A climatological study of surface freezing precipitation in Europe

“…At Inuvik, for example, as many as 53% of the radiosoundings associated with ground freezing precipitation show no warm layer. Likewise, similar but more variable results were obtained by Jeck (1996) for the continental USA, with even more frequent cases of radiosoundings with no warm nose (83% in Denver). Not shown are the same frequencies but presented by intervals with the same number of elements in the distribution each.…”

“…Such instruments as Doppler radars with diversity of polarization can be used to recognize the particle shape (and subsequently the water phase) for large particles only. A proposal was made by Jeck (1996) to establish the convention of reporting all drizzle and freezing rain encounters in terms of water content amounts in fixed dropsize intervals (i.e. aircraft water content measurements of 0.1-0.3 g m -3 for rain and about 0.1 g m -3 for drizzle).…”

Wind-tunnel investigation of icing of an inclined cylinder

“…The diameter of ordinary cloud droplets falls in the range of 1-2 µm to 40-50 µm [5][6][7]; thus, the movement of these droplets is not affected to a great extent by gravity, and the aerosol cloud may be modeled by injecting small droplets horizontally into the cold air flow. The range of droplet size in freezing drizzle (ZL) and ZR covers diameters from 50 to 500 µm, and from 500 µm to 3-4 mm, respectively [6]; therefore the effect of gravity on droplet trajectories is significant, and the phenomenon may be simulated by injecting vertically falling large droplets atomized from precooled water into the cold air flow. A series of experiments were carried out in a preceding study [8], which was completed recently by further sets of experiments.…”

The effect of droplet size and liquid water content on ice accretion and aerodynamic coefficients of tower legs

“…The dimensions of the supercooled aerosol clouds are greater in all directions under natural icing conditions (Cober et al 2001;Jeck 1996;Politovich 1989) whereas the same order of magnitude is observed for the same factors when simulating ice accretion in wind tunnel. Therefore, knowing the zone of the uniformity of the artificial aerosol clouds is essential in order to predict the local LWC and DSD.…”

“…Different combinations of these characteristics produce different types of natural icing phenomena. The LWC is in the range of a few tenth of g/m 3 under in-cloud icing conditions; however, values between 1 and 10 g/m 3 were also observed under other ambient conditions such as freezing drizzle or freezing rain (Air Force Geophysics Laboratory 1985;Cober et al 2001;Frisch et al 2000;Jeck 1996;Jeck 2002). The droplet size falls in the range of a few µm to about 50 µm under in-cloud icing conditions, whereas it takes significantly greater values under freezing drizzle (in the range of 100 µm) and freezing rain (from the range of 100 µm to several mm) conditions (Air Force Geophysics Laboratory 1985;Jeck 1996;Jeck 2002).…”