A Polar Low over the Japan Sea on 21 January 1997. Part I: Observational Analysis

Abstract

A polar low was observed over the Japan Sea on 21 January 1997. Part I of this paper focuses on the observational analyses by using all available observational data from surface meteorological stations, Geostationary Meteorological Satellite-5 (GMS-5), Sapporo and Niigata radars, 20-km resolution regional objective analysis (RANAL) data, Advanced Earth Observing System/NASA Scatterometer (ADEOS/NSCAT) wind data over oceans, and NOAA-14 Advanced Very High Resolution Radiometer (AVHRR) channel 2 and channel 4 images to document its spatial and temporal structures. The detailed evolutionary process of this polar low is described using GMS-5 data as well as Sapporo and Niigata radar data. This is the first paper to show the detailed evolution of a polar low feature by using radar data.