Gathering Weather Data pg. 79

Surface Data Instruments thermometer- filled with mercury or alcohol; expands when heated barometer- measures air pressure; mercury and vacuum chamber anemometer-measures wind speed; cupped arms that rotate as the wind blows hygrometer- measures relative humidity; uses a wet and dry bulb ceilometer-measures the height of cloud layers and sky coverage

Automated surface observing system meteorologists must have data from all these instruments at the same time National Weather Service has 1700 sites that collect data at regular intervals collected by the ASOS

Upper Level Data weather we experience is the result of changes high in the troposphere (30000 m) use balloon- borne package of sensors called a radiosonde measure temp, air pressure, and humidity constantly sent by radio signal to a ground station tracks movement of radiosonde and then data is plotted on charts very expensive

Weather Radar radar-radio detecting and ranging transmitter generates electromagnetic waves --> waves leave through the antenna waves programmed to ignore small cloud droplets and bounce off large raindrops waves are scattered (called echoes) and picked up by other antenna waves are amplified and distance is calculated radar system rotates in a circle to collect data in range of about 400 km

Doppler Radar doppler effect- when frequency of a wave changes as it moves toward or away from an observer used to plot speed of raindrops as they move toward and away a radar station provides good estimation of wind speed esp during severe thunderstorms and tornados

Weather Satellites satellites are used to take photos of earth track clouds and not necessarily precipitation coupled with weather radar

Infrared Imagery weather stations use visible light and invisible radiation infrared imagery detects differences in thermal energy allows meteorologists to determine temp of a cloud and then the type of cloud used to detect the intensity of a thunderstorm