>> Understanding weather technology

Technology, including computers, advanced radars and weather satellites, are keys to collecting the data needed for today's weather forecasting.

Instruments that measure what's around them

Many of today's weather observations instruments, such as the thermometer and barometer, were invented 200 or more years ago. These instruments are in the middle of the weather that they are measuring.

Upper air observations

Balloons that are normally launched twice a day around the world are an important source of information about the upper atmosphere. This data is needed to forecast the weather for airplanes, but also for forecasting the weather on the ground.

• NWS: Radiosonde, balloon observations
• NOAA research labs: Radiosondes
• Skew-T diagrams (This page explains the diagrams made from weather balloon observations. It is very technical)

Airplanes that gather data

Airplanes are regularly used for weather research and to gather data on hurricanes. From time to time, airplanes are sent out to observe storms over the Atlantic or Pacific that could affect the USA.

• Airplanes that fly into hurricanes

>> Remote sensing: satellites and radar

Since World War II, when radar was developed, what scientists call "remote sensing" has become more important. These devices, which include weather satellites and weather radar, measure things that are relatively far away - a few to more than 100 miles away for radar, thousands of miles away for satellites.

Weather Radar

The U.S. government has installed two different systems of weather radars around the country since the 1980s. The largest is the National Weather Service Next Generation Weather Radars (NEXRAD. These radars track weather systems over almost all of the USA, helping forecasters detect severe thunderstorm, tornadoes, the details of snow storms, and other weather that affects everyone

The Federal Aviation Administration has installed Terminal Doppler Weather Radars at 41 airports. These radars are designed to watch approach and takeoff paths at the airports to detect microbursts and other relatively small-scale hazards to aviation.

The links below have more information.

• The new weather radars use the Doppler principle to detect wind speeds and directions.
• An MIT Lincoln Lab Web site has information about aviation radar programs, including TDWR
• The University of Illinois Radar meteorology section offers a more detailed picture of how weather radar works and is used.
• NWS: Weather radar FAQ

Weather Satellites

Two kinds of satellites watch the weather.

Geostationary satellites, such as the USA's GOES series watch the weather from around 22,000 miles above the Earth. At this altitude they orbit the Earth at the same speed as the Earth is turning, which keeps the satellites above the same spot below. For more information see The University of Illinois's Geostationary satellites informational website.

Polar orbiting satellites are in much lower orbits that carry them from north-to south over Antarctica and then south to north over the Arctic. They give a more close-up view than geostationary satellites. For more information, visit the University of Illinois' Polar orbiting satellites informational website.