water
it exists in all 3 states of matter - solid - liquid and gas
condensation
the change from water vapor to liquid water
Specific Humidity
the number of grams of water vapor in a kilogram of air
saturated
the point at which condensation equals the point of evaporation
Realtive Humidity
when meterologist use this term they are telling us how near the air is to reaching its maxiumum capacity for holding water vapor - it is usually stated in a percentage
Psychrometer
instrument used to measure humidity - it consists of 2 thermometers - one is a dry bublb and the other a wet bulb
dew point
the temperaturee at which saturation occurs and condensation begins - it is a measure of amount of water vapor in the air
condensation nuclei
microscopic particles on which water vapor condenses to form cloud droplets - they are tiny particles
radiation fog
forms when the night sky is clear and the ground loses heat rapidly through radiation - the resulting fog is at ground level - most often found in humid valley's near rivers or lakes and most frequent in late fall and early winter
Condensation of water vapor in the air occurs when the temp drops below the point at which the airs'
capacity and specific humidity are the same
Fog droplets remain suspended in air because
they are supported by slight movements of air
Particles that do not usually act as condensation nuclei are
ozone particles
If both wet bulb and dry bulb thermometers read the same the air is
saturated
materail used to provide condensation nuclei in artifical rainmaing
silver iodide
in a cumulonimbus cloud, what keeps the rising air inside the cloud warmer & less dense than the air around it?
heat from condensation
When the temperature of a cloud is below -20 degress C, the cloud consists almost entirely of
snow and ice crystals
A stratus cloud
forms in stable air
Where can clouds form?
any altitude in the troposphere
If a cumulus cloud does not have a continuous supply of moist air it may
evaporate
meterologist can predict the condensation level and how tall clouds will grow by considering
the air tem at different elevations - dewpoint & the cooling and rising of air
which is not a form of precipitation
fog
when warm mosit winds blow over snow covered grounds, this is most likely to occurair
advection fog
Nimbostratus Clouds
the dark grey layers of clouds that produce a steady rain
Cumulonimbus Clouds
form when warm mosit air rises & cools - these type of clouds have a condensation level at the BOTTOM of the cloud - the tallest of these type of clouds can rise as 2x the height of Mt Everest
Cumulus Clouds
fluffy and white with flat bases - formed by vertical rising air currents