CH. 2SEC. 5
PRECIPITATION
Objectives:1. What are the common types of precipitation?2. How is precipitation measured?
precipitation•any form of water that falls from clouds & reaches Earth’s surface
TRUE OR FALSE
•All clouds produce
precipitation.
precipitation•cloud droplets or ice crystals must grow heavy enough to fall thru air
types of precipitation
1. rain
2. sleet
3. freezing rain
4. hail
5. snow
rain• most common type of precipitation
• @ least 0.5 mm in diameter
drizzle
• rain < 0.5 mm
• mist-even smaller
• fall from stratus clouds
• raindrops freeze when touch cold surface (ground)
freezing rain
sleet•raindrops freeze as falling
•< 0.5 mm in diameter
Tiny ice pellets aretossed up and down incumulonimbus clouds,growing larger as theygain layers of ice.
Eventually the icepellets grow heavyenough to fall tothe ground as hail.
hail
hail• ice pellets add layers
of ice as carried up & down in cumulonimbus clouds during thunderstorms
• >5mm in diameter
snow•water vapor in cloud converts directly ice crystals
rain measured w/ rain gauge=
–open ended can or tube that collects rainfall
Rain Gauge
snowfall measured by:
1. using ruler or
2. melting collected snow & measuring depth of water it makes
drought
• long period of unusually low precipitation
cloud seeding• small planes used to sprinkle chemicals clouds to try to make rain
Precipitation Description
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