Lesson 9-3
psychrometers
a common type of hygrometer that uses the cooling effect of evaporation to measure the humidity
transmissometer
a device that measures visibility
maximum-minimum thermometer
a special type of liquid thermometer used to record the highest and lowest temperatures of the day and night during a particular period
automatic weather stations
allow atmospheric conditions to be monitored without a meteorologist at the site
station model
an arrangement of symbols and numbers that show the weather conditions recorded at a weather station
aneroid barometer
an instrument that measures changes in air pressure without using a liquid; changes in the shape of an airtight metal box cause a needle on the barometer dial to move
mercury barometer
an instrument that measures changes in air pressure, consisting of a glass tube partially filled with mercury, with its open end resting in a dish of mercury
hygrometer
an instrument used to measure relative humidity
rain gauge
an instrument used to measure the amount of precipitation that falls
weather vane
an instrument used to measure the direction of the wind
liquid thermometer
contains colored alcohol or mercury that expands when heated and rises in a narrow tube
doppler radar
device that can measure both precipitation and the speed and direction of winds
hair hygrometer
device that uses a strand of hair to measure relative humidity
radar
device that uses radio waves to detect objects and measure their distance
thermometer
device used to measure air temperature
barometer
device used to measure atmospheric pressure
ceilometer
device used to measure the distance from the ground to the base of clouds
supercomputers
extremely powerful computers used by meteorologists capable of rapidly performing complex calculations
anemometer
instrument that measures wind speeds near the earth's surface
electrical thermometer
instrument used to measure temperature based on the increased flow of electricity through certain materials when the materials are heated
radiosondes
instruments that simultaneously measure and transmit meteorological data from balloons to weather stations below
isotherms
lines of equal heat; broken lines the connect stations that have the same temperature
isobars
lines of equal pressure used to represent the air pressures that have been recorded at each station
surface weather charts
maps that give a summary of the weather conditions throughout the entire country at a single point in time
weather forecasts
predictions of what the weather will be like in the near future
barograph
records changes in air pressure over time
thermograph
records temperature changes over time
weather satellite
satellites used to record temperature, cloud cover, precipitation, etc.
sounding rockets
small, inexpensive rockets that can launch small, light instruments up to several hundred miles high before the rockets fall back to earth
bimetallic strip
strip made of 2 different metals that expand at different rates; this causes the strip to bend when heated.
visibility
the farthest distance at which objects can be distinguished
Stevenson screen
type of weather instrument shelter having slatted sides and a slatted base to allow air to freely flow through the boxlike shelter
bar
unit of pressure used in meteorology