Research on Monitoring Downburst by Using Array Weather Radar

The downburst is a short-time and smallscale strong convective weather system, which develops and dissipates extremely fast, and produces strong wind shear near the ground, and has a serious impact on the safety of aircrafts. The Array Weather Radar covers the elevation angle between 0 and 90 °, only takes 12s for a full volume scan, and can obtain high spatial and temporal resolution detection data. In order to improve the monitoring and early warning capability of the downburst, in this paper, a micro-downburst and a convective precipitation detected by the Array Weather Radar at Changsha Huanghua Airport in Hunan Province is analyzed by using the unit area equivalent potential value change and the echo characteristics of the AWR during the 15 minutes before the downburst happened. The data from airport ground automatic stations are analyzed and verified. The results show that the Array Weather Radar has significant advantages in monitoring short-time andsmall-scale weather systems such as downbursts. The convective process on May 20 2018 produced a local downdraft with the surface maximum wind speed of 11.6 m/s, and the release ratio of equivalent potential energy per unit area was over 30%; The water vapor starts to condense near the zero layer of the atmosphere and forms several storm cells The coalescence growth of the storm cells leads to form a new storm and accelerates the development of the new storm. The mid-level radial convergence and near-surface divergence of the echo are consistent with the wind speed and direction changes of the surface automatic meteorological station. The increases of the dew point temperature and pressure from automatic weather station have a certain indicative effect on the downdraft of storm. The AWR can give the warning information of 13 minutes before the surface wind speed reaches its maximum valve, and improve the monitoring and early warning on short-time small-scale weather systems such as downbursts by analyzing the effective potential energy release ratio per unit area.