Weather : Meteorology and Weather Prediction

Radar and Satellite Technology:

Radars

The word radar is an acronym from "Radio Detection and Ranging". Radar images are useful for locating precipitation.

A radar sends a pulse of energy into the atmosphere and if any precipitation is intercepted by the energy, part of the energy is scattered back to the radar. These returned signals, called "radar echoes", are assembled to produce radar images.

Sending and Receiving Signals (detecting a target)

The radar creates an electromagnetic energy pulse which is focused by an antenna and transmitted through the atmosphere. Objects in the path of this electromagnetic pulse, called targets, scatter the electromagnetic energy. Some of that energy is scattered back toward the radar.

The receiving antenna (which is normally also the transmitting antenna) gathers this back-scattered radiation and feeds it to a device called a receiver.

The location of the colored radar echoes indicate where precipitation is falling and the various colors indicate the intensity of the precipitation through the color code in the lower left corner of the image.

Satellites:

A satellite is defined as a man-made object put into orbit around a celestial body, like the earth or the moon.

Satellites serve a wide variety of purposes from transmission of television signals via communication satellites to guidance and tracking systems of defense satellites. For meteorologists, satellites provide a comprehensive view of the world's weather. On April 1, 1960, the first weather satellite was launched into orbit from the United States. Since then, weather satellites have been launched into orbit and their capabilities have improved significantly. Satellites carry imager and sounder instruments enabling them to image clouds, monitor earth's surface temperature and water vapor fields, and sound the atmosphere for its vertical thermal and vapor structures. Today, not only do satellites observe clouds, but measure other non- visible radiation from the earth and atmosphere. This helps us to estimate such aspects as crop and soil conditions.

Acknowledgement: The above information is taken from the following website:

http://ww2010.atmos.uiuc.edu/(Gh)/guides/rs/rad/img/wsr.rxml