Water in the Atmosphere
+
Weather
Chapter 23+24
Latent heat –
• Evaporation (__  ___)& Condensation (__  ___)
• Sublimation –
• Deposition
NO LIQUID PHASE!
Humidity –
Controlled by rates of __________________ and
__________________
– Saturated air: condensation = evaporation
– If condensation rate is greater than evaporation
rate, rain droplets form
– Part of total atmospheric pressure
Dew Point –
• Absolute
Humidity
• Relative
Humidity –
Clouds
• Clouds are comprised of liquid droplets of various
sizes and/or ice crystals
• __________ ___________allow water vapor to
condense on it to form raindrops
Expansional Cooling & Compressional
Warming
Adiabatic cooling –
Adiabatic Lapse Rate –
how fast a parcel of
air warms up or cools
down because of
rising or sinking
Advective Cooling-
CA Marine layer: warm air over ocean flows inland, ground is
cold and causes condensation
Clouds are characterized according to their
height and vertical development:
• High Clouds:
– cirrus (Ci)
– cirrostratus (Cs)
– cirrocumulus (Cc
• Middle Clouds
– Altostratus (As)
– Altocumulus (Ac)
• Low Clouds:
– Stratus (St)
– Stratocumulus (Sc)
– Nimbostratus (Ns)
• Clouds with vertical
development:
– Cumulus (Cu)
– Cumulonimbus (Cb)
Precipitation
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


• Rain gauge – collect rain in cylinder,
measure in inches
• Snow – measured using a yardstick
• Coalescence –
• Supercooling – substance cooled below
freezing, condensation or sublimation
point without phase changes
• Cloud seeding –
Natural Science Warm Up
1/29/14
Write the question, please! 
1. Fair weather cloud- _____________
2. Lowest level cloud, may cause light drizzle or fog_______________
3. Fluffy and cotton-like cloud, most likely to cause
precipitation- ____________
Precipitation
1. The sun heats up water on the surface of the earth, turning it into vapor.
2. Water vapor is less dense, which causes it to rise.
3. The vapor cools when it reaches the dew point and condenses back into
liquid in the form of clouds.
4. The water droplets in the clouds coalesce until they are too heavy for the
atmosphere to hold them and the droplets fall as precipitation.
Hail normally occurs in thunderstorms
and is the result of strong updrafts that
repeatedly carry growing chunks of ice
upwards into the clouds. Once the hail
stones become too heavy to be lifted by
the updrafts, they fall to the ground.