Transcript Weather Factors

Weather Factors
Chapter Two
Energy in the Atmosphere


Most energy from the sun reaches Earth
in the form of visible light and infrared
radiation, and a small amount of
ultraviolet radiation.
When Earth’s surface is heated, it
radiates some of the energy back into
the atmosphere as infrared radiation.
Key Terms:






Electromagnetic waves: A form of energy that can travel
through space.
Radiation: The direct transfer of energy by
electromagnetic waves.
Infrared radiation: A form of energy with wavelengths that
are longer than visible light.
Ultraviolet radiation: A form of energy with wavelengths
that are shorter than visible light.
Scattering: Reflections of light in all directions
Greenhouse Effect: The process by which heat is
trapped in the atmosphere by wayer vapor, carbon
dioxide, methane, and other gases that form a “blanket”
around Earth.
Heat Transfer


The energy of motion in the molecules of
a substance is called thermal energy.
Three forms of heat transfer work
together to heat the troposphere. They
are: Radiation
Conduction
Convection
Key Terms






Thermal energy: The energy of motion in the molecules of a
substance.
Temperature: The average amount of energy of motion in the
molecules of a substance.
Thermometer: An instrument used to measure temperature
consisting of a thin, glass tube with a bulb on one end that
contains a liquid (usually) mercury or alcohol.
Heat: The energy transferred from a hotter object to a cooler
one.
Conduction: The direct transfer of heat from one substance to
another substance that is touching.
Convection: The transfer of heat by the movement of a fluid.
Winds




All winds are caused by differences in air
pressure.
Local winds are caused by unequal heating of
Earth’s surface within a small area.
The movement of air between the equator and
the poles produces global winds.
The major global wind belts are the trade
winds, the prevailing westerlies and the polar
easterlies.
Key Terms









Wind: The horizontal movement of air from an area of high pressure
to an area of lower pressure.
Anemometer: An instrument used to measure wind speed.
Wind-chill factor: Increased cooling caused by the wind.
Local wind: Winds that blow over short distances.
Global wind: Winds that blow steadily from specific directions over
long distances.
Sea Breeze: The flow of air from an ocean or lake to the land.
Land breeze: The flow of air from land to a body of water.
Coriolis effect: The way Earth’s rotation makes winds in the Northern
Hemisphere curve to the right and winds in the Southern Hemisphere
curve to the left.
Latitude: The distance from the equator, measured in degrees.
Water in the Atmosphere

Clouds of all kinds form when water in
the air becomes liquid water or ice
crystals.
Types of Clouds

Meteorologists classify clouds into three
main types: Cumulus
Stratus
Cirrus
Key Terms









Evaporation: The process in which water molecules iin liquid water
escape into the air as water vapor.
Humidity: A measure of the amount of water vapor in the air.
Relative humidity: The percentage of water vapor in the air compared
to the maximum amount the air cloud hold at that temperature.
Psychrometer: An instrument used to measure relative humidity,
consisting of a wet-bulb thermometer and a dry-bulb thermometer.
Condensation: The process by which molecules of water vapoar in the
air become liquid water.
Dew Point: The temperature in which condensation begins.
Cumulus: Clouds that form least than 2 kilometers above the ground
and look like fluffy, rounded piles of cotton.
Stratus: Clouds that form in layers.
Cirrus: Wispy, feathery clouds made mostly of ice crystals that form at
high levels, above about 6 kilometers.
Precipitation



Rain, sleet, freezing rain, hail and snow
Rain is measured with a rain gauge
Scientists have used cloud seeding to
produce rain and to clear fog from
airports
Key Terms



Precipitation: Any form of water that falls from
clouds and reaches Earth’s surface.
Rain Gauge: An instrument used to measure
the amount of precipitation, consisting of an
open-ended can topped by a collecting funnel
and having a collecting tube and measuring
scale inside.
Drought: Long periods of low precipitation.