NSSL | Education | Ideas

Ideas for Teaching

• Stereo photography
• Why radar can't (usually) see tornadoes
• Graphing information
• Vectors for wind speed
• Calculating %
• Simple math
• Not so simple math
• Wildflowers & rainfall

Graphing Data

Page 1 | Page 2 | Page 3 | Page 4

Graphing Radar Beam Heights

Meteorologists are well aware that weather radars are generally set to scan the atmosphere at fixed elevation angles. This is especially true of the WSR-88D, or NEXRAD, Doppler radars. These radars are what the National Weather Service uses in their daily forecast and warning operations, but the radars are also used by the FAA, DOD, and others. In order to meet the needs of several users the radars were set to scan in certain patterns.

In all scanning patterns the radar dish is tilted to a particular angle above ground and then rotated 360 degrees (i.e., the dish turns to point in all directions from north to east to south to west and back to north). When this revolution, or scan, is done the dish is elevated to a higher angle and rotates around again. This continues until the radar has sampled a nearly 3-D volume around the radar.

But these discrete angles mean that storms are not sampled continuously and this can impact interpretation of radar data of storms. For example, the cloud top height calculated from radar often seems to jump around. Here's why.

Page 3...

Last updated: March 26, 2002
Created by: DSZ