Lemon technique
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The Lemon Technique is a method used by weather radar operators to determine the relative strength of thunderstorm cells in a vertically sheared environment. It is named for Leslie R. Lemon, the creator of the current conceptual model of a supercell.
This method uses modern weather radar to measure quantities such as height (echo tops), reflectivity, and location and to show features and trends described by Lemon. These features include:
- Updraft tilt - The tilt of the main updraft is an indication of the strength of the updraft, with nearly vertical tilts indicating stronger updrafts.
- WER or Weak Echo Region - An area of markedly lower reflectivity, resulting from an increase in updraft strength.
- BWER or Bounded Weak Echo Region - Another area of markedly lower reflectivity, now bounded by an area of high reflectivity. This is observed as a "hole" in reflectivity, and is caused by an updraft powerful enough to prevent ice and liquid from reaching the ground. This powerful updraft is often an indication of, or is facilitated by, a mesocyclone. It should be noted, however, that a mesocyclone is not strictly necessary for BWER development. Storm rotation can be reliably detected by Doppler radar.
References
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