Doppler radar observations of a wintertime anticyclonic misocyclone associated with surface wind gust on the coast of the Sea of Japan

Abstract

On December 11, 2012, a wind gust caused an F0-intensity wind damage in the Shonai area, Yamagata Prefecture, Japan. This paper provides an overview of an anticyclonic misocyclone (i.e., anticyclonic circulation in the Doppler velocity) related to a wind gust from X-band Doppler radar data. The anticyclonic misocyclone was embedded within a cell with a spiral echo diameter of approximately 3-4 km. The misocyclone over the Sea of Japan moved southeastward at a speed of 11 m s⁻¹, made landfall, and passed over the damaged area; this timing is consistent with the Japan Meteorological Agency (JMA) wind damage assessment. Over the damaged area, the diameter of the misocyclone in the Doppler velocity was estimated to be smaller than 893 m, and the peak tangential wind speed and the vorticity of the vortex were estimated to be at least 8 m s⁻¹ and −3.6 × 10⁻² sec⁻¹, respectively. This study discusses various possible explanations for the relationship between the misocyclone and wind gust and provides a first overview of a wintertime anticyclonic misocyclone associated with a surface wind gust on the coast of the Sea of Japan and may provide useful insights to the understanding of wintertime vortices.