Applicability of quantitative wind speed estimation method during the downburst event in Guizhou on May 4, 2025

Currently, downburst identification and warning algorithms based on weather radar in China cannot effectively estimate the intensity and wind speed of downbursts. The Wuhan Institute of Heavy Rain, China Meteorological Administration, has newly developed a method for estimating the extreme wind speed of thunderstorm gales based on dual-polarization weather radar hydrometeor classification products, which is referred to as the Extreme wind speed Estimation method based on Hydrometeor Classification (EESonHC). This study utilized sounding meteorological data, ground automatic weather station observations, and dual-polarization weather radar products to analyze the application effectiveness and influencing factors of the EESonHC method for the downburst event that occurred over the southwestern Guizhou mountainous areas on May 4, 2025 (hereinafter referred to as the "5.04" downburst event). For this event, the EESonHC method accurately captured the temporal evolution of surface winds generated by the supercell storm near Guiyang, estimating extreme wind speeds slightly higher than surface observations with a 10-minute lead time; it effectively identified the storm from the two storm cells that produced downburst wind speeds exceeding 25 m·s⁻¹. Due to severe terrain blockage affecting the 0.5° elevation radar data in Guizhou's mountainous areas, extreme wind speeds estimated using 1.5° elevation radar data were more accurate. The vertical acceleration threshold within the storm cell in the EESonHC method is related to raindrop size distribution characteristics. Thresholds established based on case studies from North China and the Jianghuai regions remain applicable to Guizhou. This study demonstrates that the EESonHC method works for both plain regions and mountainous regions such as Southwest China, and it is applicable for both multicell storms and supercell storms.