Skip to content
Know.itKnow.it
Create an animated lesson
On request

This article is free to read. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

How do weather satellites work?

ScienceLesson on requestFree to read

Quick answer

Weather satellites carry cameras and sensors that measure visible light, infrared heat and microwaves coming from Earth. Orbiting the planet, they radio this data to ground stations, where computers convert it into cloud images, temperature and moisture maps, and wind measurements that feed the forecast models used every day.

Weather satellites work by carrying sensors that measure radiation from Earth's surface, oceans and atmosphere, then radioing those measurements to ground stations. Computers turn the data into the cloud images, temperature maps and storm tracks used in daily forecasts.

Step by step

  1. A satellite in geostationary or polar orbit points its instruments down at Earth.
  2. Sensors record visible light, infrared heat and microwave radiation from clouds, land and sea.
  3. An onboard transmitter sends the raw measurements by radio to ground stations.
  4. Computers correct the data for the satellite's position and viewing angle.
  5. Images and temperature or moisture maps are produced and compared with earlier passes.
  6. Wind and humidity values are fed into forecast models that predict coming weather.

Key things to understand

  1. Satellites orbit either in geostationary orbit, staying fixed over one spot, or in polar orbit, sweeping the whole globe as Earth turns beneath them.
  2. Visible-light sensors photograph clouds much as a camera does, showing their shape and brightness only where the Sun is shining.
  3. Infrared sensors measure the heat radiated by cloud tops and land, so they can track weather day and night.
  4. Microwave and radar sensors detect water droplets, ice and water vapour inside clouds, revealing rain rates and hidden storm structure.
  5. Ground computers compare successive images to calculate wind speeds and directions, then feed the numbers into forecast models.

Labelled diagram

  1. Orbit

    Satellite circles Earth, fixed over one spot or sweeping pole to pole.

  2. Sensors

    Instruments measure visible light, infrared heat and microwave radiation.

  3. Downlink

    Radio transmitter sends raw measurements to a ground station dish.

  4. Processing

    Computers correct, combine and map the data into images.

  5. Forecast

    Wind and moisture values feed models that predict coming weather.

From orbit to forecast

Real-world examples

  • Geostationary satellites parked over the equator give the continuous cloud loops seen on television weather bulletins.
  • Polar-orbiting satellites pass over the poles and scan the whole globe twice a day at high detail.
  • Hurricane trackers use infrared images of cloud tops to locate the eye and estimate storm strength.
  • Farmers and pilots check satellite rainfall and cloud maps before deciding when to work or fly.

Common mistake

✗ Myth: Weather satellites take ordinary photographs of clouds.

✓ Fact: Their imagers record many wavelength bands, including infrared heat and microwaves that eyes cannot see. Many familiar cloud pictures, especially at night, are computer images built from those invisible measurements.

People also ask

How do weather satellites help predict hurricanes?
Infrared and microwave sensors track the height and coldness of cloud tops and the rain hidden inside, which reveal where air is rising fastest. Comparing successive images shows the storm's speed and direction. Forecasters use these measurements to estimate intensity and project where the hurricane will go.
What is the difference between geostationary and polar orbiting satellites?
A geostationary satellite orbits at the same rate Earth turns, so it hangs over one point and watches continuously. A polar-orbiting satellite flies much lower, passing near the poles as Earth rotates beneath it, so it sees the whole globe at finer detail about twice a day.
How is satellite data used in weather forecasting?
Sensors measure temperature, moisture and cloud at many heights, and computers turn these into grids of numbers. Forecast models start from those grids and calculate how the atmosphere will change. Without satellite data, forecasts for oceans and remote regions would be far less accurate.
Why do weather satellites sometimes stop working during a storm?
They usually keep working; the ground link is what can suffer. Heavy rain and thick cloud absorb the radio signal between satellite and dish, so data can arrive late or with gaps. Engineers route the signal through backup ground stations to reduce this.
How often do weather satellites send back pictures?
Geostationary satellites send a full-disc image roughly every 10 to 15 minutes, and some scan smaller regions more often. Polar-orbiting satellites pass over the same area about twice a day, but at much finer detail. Forecasters combine both for frequent, sharp coverage.
Can weather satellites see inside clouds?
Not with ordinary cameras, which only see the top. Microwave and radar instruments penetrate cloud and sense the water and ice inside, while infrared shows how cold the cloud top is. Cold, high tops usually mean stronger upward motion and heavier rain.
Do weather satellites measure temperature on the ground?
They measure radiation, not temperature directly, and computers convert it. Infrared bands estimate the temperature of the surface and of cloud tops; microwave bands estimate temperature and moisture at several heights in the atmosphere. Ground stations and balloons check these estimates.

Part of the guide: Space & Astronomy →