On January 28, 2009, the pilot of a military aircraft near Kuopio Airport in south-central Finland reported "heavy icing conditions" between 10,000 and 14,000 feet (3000-4300 meters above sea level). Jarkko Hirvonen of the Finnish Meteorological Institute examined the weather conditions in the region during this icing event report, and concluded that the actual conditions would only have caused light to moderate icing, rather than the heavy icing in the pilot report. (He noted that pilot reports of icing can be "highly subjective".)
One of the key elements of Hirvonen's analysis was Cloudsat data, which he utilized by employing the Giovanni A-Train data interface. Hirvonen generated Cloudsat profiles of Ice Water Content and Liquid Water Content from a Cloudsat track that passed about 380 km from the airport, with a 3 hour time difference. Despite this difference, Cloudsat data were used to analyze the middle cloud layer in which the icing occurred. Hirvonen's primary conclusion was that the middle cloud layer was mainly composed of (supercooled) liquid water, and there was only a small amount of cloud ice. His analysis of the satellite data also indicated it was unlikely that there was a significant presence of supercooled large droplets (SLDs) which could have caused heavy icing, even though meteorological analysis suggested that some SLDs could have been formed at that altitude.
Data from MODIS on the Aqua satellite, which is also in the A-Train constellation, were also used to analyze the event.
The study was presented as a poster at the 13th International Workshop on Atmospheric Icing of Structures (IWAIS), held September 8-11 in Andermatt, Switzerland; an Extended Abstract appears in the meeting proceedings. The proceedings can be downloaded as a zip file from the following site:
IWAIS 2009 Proceedings
Hirvonen's paper is in the "Cost Action 727 Working Group 1 – Modelling of Icing" poster sesssion.