EOSC 114 Lecture Notes - Lecture 19: Advection, Leading Edge, Microburst
27 Feb 2018
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Document Summary
Cumulonimbus (thunderstorms) are mad of large cellst aht evolve during 15-20 inutes. Most thunderstorms (tstorms) contain 2 or more cells, and are called multicell thunderstorms. Sometimes a very large, rotating single-cell thunderstorm forms, called a supercell tstorm. They can cause the most violent tornadoes, large hail frequent lightning, heavy rain, strong wings. Supercell types: low precipitation, classical, high precipitation. Some are in-between and are called hybrid storms. Radar can"t show clouds just how much rain which is noted by the rain disaster intensity scale dbz is logarithmic however, its in db go up 10 db = 10 times the intensity of rainfall. Horizontal wind speeds near ground of up to 250 km/h. Downburst: cold (dense) air sinking: tstorm can create dense air where rain falls; dur to evaporative cooling, often invisible, but a hazard to aricrafts. Safety: avoid weak buildings and trees that could fall. Virga: when precipitation completely evaporates before hitting the ground.
