1 Section 03: Global Weather

2 Lesson: 01 Professional Forecasting and Technology Section 4.9 Pages

3 Meteorologist Professional person who studies the weather. Meteorologist: 1. Temperature 2. Air pressure, 3. Winds, 4. humidity, 5. Precipitation6. Cloud cover 7. Wind speed 8. Direction

4 Meteorologist Information gathered at weather stations.

5 Meteorologist The main problem of course was that the everyday view of the weather was from the surface of the earth.

6 Satellites In the 1960's when the first satellite. Weather satellites now give us a birds eye view of weather systems. The weather satellites still collected the same basic data that the meteorologist collected before.

7 Weather Station vs Satellites Difference between satellites and weather station is satellites are orbiting at extremely high altitudes and produce a very large view of the surface of the earth.

8 Satellites Satellite technology allows us to give warnings days in advance of approaching weather systems. Stormy weather …dark circulating clouds Clear weather… absence of clouds

9 Devices used to forecast weather today 1. Weather satellites 2. Weather balloons 3. Radar.

10 1. Satellites…Two types A. Low-orbit Satellites Orbit at about 1000 km above the earth. Send back information on global winds, air temperature and humidity levels in the upper atmosphere.

11 1. Satellites…Two types B. High-orbit Satellites Orbit at about km. These satellites take pictures of cloud cover. Take Infra red (IR) images which show the heat being given off by the earth. Take a much larger picture of the earth.

12 Image of satellites at different levels.

13 2. Weather Balloons Large helium filled balloons that are released into the atmosphere on a daily basis. The weather balloon carries a radiosonde up through the atmosphere. Radiosonde computer instruments that record temperature, pressure, humidity and amount of ice crystals.

14 2. Weather Balloon

15 3. Radar Radar stands for Radio Detection And Ranging. Developed during World War II, the technology sends out a radio wave. If the radio wave hits an object like an airplane, the radio wave bounced back. Measuring the time it took the wave to bounce back you could calculate how far away the object was.

16 3. Radar The interesting thing is that they discovered rain showers also caused the radar wave to bounce back. Radar operators were getting "fuzzy" data but could accurately position the rain shower!

17 3. Radar Meteorologist now use this similar technology to track large rain clouds. Doppler radar as it is sometimes called can detect where the rain is falling and can now even tell us how much rain is falling.

18 3. Radar Radar is particularly useful for detecting and tracking thunderstorms and tornados. These storm features develop too quickly and are too small to be detected by weather satellites.

19 3. Radar