Assessing the Risks of Vessel Icing and Aviation Hazards during Downslope Windstorms in the Russian Arctic

Abstract

Downslope windstorms are known sources of hazardous weather, such as severe gusty winds, rapid temperature changes, ship icing, strong turbulence and others, posing a great danger to people and infrastructure. This paper investigates the risks of ship icing and aviation hazards (rapid changes in the angle of attack and gust load factor) during downslope windstorms in five regions in the Russian Arctic based on observational data, reanalysis, and mesoscale numerical modeling. The highest frequency of ship icing was found during downslope windstorms downstream from Svalbard and Novaya Zemlya. Icing is rare during Tiksi and Wrangel Island downslope windstorms due to almost permanent sea ice cover during the cold season, while icing is absent during very warm Pevek downslope windstorm even in the ice-free conditions. Conditions for heavy icing are rather frequent (up to 5% of cases in winter) during Novaya Zemlya downslope windstorms and less frequent (up to 0.5% in spring) during Svalbard windstorm. The presence of downslope windstorms in those regions causes an increase in the maximum icing rate by about 2 times. Strong aviation turbulence hazardous for light aircraft is typical for all considered regions with downslope windstorms; it is observed mainly at an altitude of 1 to 4 km above the surface. Hazardous turbulence for jet aircraft like Boeing 737 on its cruising flight levels was found on Svalbard and in Tiksi region in 10–15% of cases during strong downslope windstorms.

Keywords

• ship icing
• downslope windstorms
• WRF-ARW
• clear-air turbulence
• bora
• Arctic