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The Precipitation Ladder http://www.islandnet.com/~see/weather/elements/makerain.htm http://www.islandnet.com/~see/weather/elements/makerain.htm Cloud Droplets and Raindrops More in Lab 7 later today BTW, GOES = Geostationary Operational Environmental Satellite Cloud Droplets and Raindrops
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The Precipitation Ladder http://www.islandnet.com/~see/weather/elements/makerain.htm http://www.islandnet.com/~see/weather/elements/makerain.htm
Cloud Droplets and Raindrops More in Lab 7 later today BTW, GOES = Geostationary Operational Environmental Satellite
Cloud Droplets and Raindrops Precipitation Ladder
Step 10: Growth – p. 90Three ways to grow over 30 diameters from cloud droplet to raindrop • Direct deposition – “accretion” • Large fall faster and catch up with smaller drops – collide and “coalesce” • “Supercooled” water = liquid water below freezing point (down to 40 oC) spontaneously migrates to nearby ice crystals Snowflakes! • Complicated physics • Bergeron process
Raindrops, so many raindrops Link to the Weather Doctor
Snowflake shapes – p. 96 • Plates • Stellars • Columns • Needles • Spatial dendrites • Capped columns • Irregular crystals • Not Snow: Graupel – Sleet - Hail
Solid Precipitation other than snow Graupel(?), Sleet, Hail, Rime
Graupel – p. 97 A soft granular mass of frozen cloud droplets
Sleet – p. 97 Frozen drizzle, with some complications
Rime – p. 98 More of a “deposition” than precipitation Some kinds of it are called “hoar frost” Some purdy pilfered pitchers follow:
Hail – p. 98 Formed in updrafts in large CB clouds Has multiple layers from partial melting and refreezing
Raindrops • Not tear-drop shaped • Different classification by size • Showers • From cumulonimbus or cumulus congestus • Up to 6 mm • Rain • From nimbostratus • 1 – 2 mm • Drizzle • From stratus • .1 - .5 mm, effectively soaking into ground • Mist • .05 - .8 mm, from stratus • Oregon Mist or Scotch Mist