Influence of Novaya Zemlya Bora on Sea Waves: Satellite Measurements and Numerical Modeling

Abstract

This paper investigates for the first time sea waves during Novaya Zemlya bora—a downslope windstorm on the western coast of the archipelago during eastern winds—using a statistical and case-study approach. Statistical analysis of altimeter data off the western coast of Novaya Zemlya during bora shows that, despite strong wind forcing, the frequency of hazard wave heights was low due to the limited fetch. This result was confirmed by the high-resolution numerical simulations of two severe bora episodes. However, the influence of bora on sea waves in some cases was significant: bora increased wave height at a distance from shore greater than 200 km and wave height anomaly was up to 2–3 m. The influence of the wind input parametrization choice during bora is great in the coastal region; however, parametrizations with fetch-limited modifications and strong-wind adopted aerodynamic drag coefficient do not improve the modeling results in the open sea where altimeter data are available.

Keywords

• downslope windstorms
• WaveWatch3
• WRF-ARW
• Novaya Zemlya
• fetch-limited waves