Precipitation Structure of Monsoon Rainfall Systems using High-Resolution Vertically Pointing Radar

In East Asia, heavy rain events are mostly associated with tropical cyclones and monsoon systems. The monsoonal flows interact with complex terrains often produce severe heavy rains and cause many devastating disasters. The precipitation structure of monsoon rainfall systems are not well understood, especially in the areas surrounded by complex terrain.

In 2008, Southwest Monsoon Experiment (SoWMEX) / Terrain-influenced Monsoon Rainfall Experiment (TiMREX) jointly proposed by Taiwan and US scientists were conducted at southwest region of Taiwan. Many interesting features of the monsoon rainfall events were observed. However, it was found that the precipitation structure in the mountain region, especially in the valley, could not be well sampled because of severe beam blockage by the complex topography.

To overcome the problem mentioned above, the vertically pointing radar was introduced into Taiwan before the end of 2012. It is a pulsed Doppler radar operating at 3.054 GHz, and the beamwidth is 3.3. The radar measures the vertical profile of reflectivity, Doppler fall speed, and its spectral width up to 20400 m at 60-m resolution every 60 s.

During spring and Mei-Yu season in 2013, the radar deployed in north Taiwan kept observation with the disdrometer. The observed brightband height is in good agreement with the climatic melting height. But sometimes the brightband precipitation shows higher rain rate as strong as the convective precipitation. The detailed analysis and the classification for the precipitation structure are ongoing.