Characterizing Icing and Non-icing Events in Cold and Alpine Environments Using Instrumentation and NASA Langley Cloud Products

One of the goals of the NASA EPSCoR (Experimental Program to Stimulate Competitive Research) Icing Assessments in Cold and Alpine Environments Project is to study the environmental factors that lead to icing conditions in mountainous terrain. One part of this research effort involved using instrumentation at mountainous locations in New England during the 2011-2012 winter season to provide icing information for validation of icing forecast models. This part of the project focused on analyzing the instrument data to characterize differences between icing and non-icing conditions, with the focus being on the Mount Washington region of New Hampshire.

There were two prongs to this research. The first prong examined the differences in the synoptic and surface environments between icing and non-icing events. Icing events were defined as periods where icing was reported on Mount Washington for at least 24 consecutive hours, based on raw METAR observations at the summit. With this definition, 34 icing events were found with a peak event lasting 93 hours. Synoptic and surface observation analyses were performed for these 34 events as well as 10 non-icing events (no icing reported in a 24 hour period) using raw METAR observations at Mount Washington and archived frontal analysis charts from the Hydrometeorological Prediction Center.

The second prong of this research project dealt with analyzing data retrieved from specialized instrumentation placed in the study area this past winter. These instruments included radiometers, ceilometers, and ice detectors. Daily databases from 1 November 2011 to 30 April 2012 were created comparing parameters from all instrumentation to develop patterns between icing and non-icing periods. Cloud products developed through GOES satellite imagery (icing potential, cloud-base height, and cloud-top height) were retrieved from the NASA Langley Research Center to determine its accuracy in locating icing and non-icing environments and were compared to the instrument measurements.