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National Weather Service - NWS Billings WSR-88D to Receive Dual Polarization Upgrade
During a two-week period, beginning October 24, 2011 and ending November 6, 2011, the Doppler radar at the National
Weather Service Forecast office in Billings, Montana will undergo an upgrade to incorporate new technology.
During the two-week installation process, the Billings (BYZ) radar will be taken offline. Neighboring NWS Doppler radars in
Glasgow, MT,
Great Falls, MT,
Riverton, WY, and
Rapid City, SD
will be accessible to help monitor portions of central and southeast Montana, as well as northern Wyoming.
Dual Polarization (or "dual-pol") technology will add an additional 14 products to the suite of data already available to NWS forecasters.
These tools will assist forecasters in the warning and forecast process.
Why upgrade to Dual Polarization Radar?
By comparing the power and timing of energy returned to the radar from both horizontal and vertical pulses, we can glean information such as the size,
shape, and composition of precipitation particles.
What are the Potential Benefits of Dual-Pol?
Better estimation of total precipitation
Better estimation of the size distribution of hydrometeors
Improved ability to identify areas of heavy rainfall (flash flooding potential)
Improved detection and mitigation of non-weather echoes
Easier identification of the melting layer (helpful for identifying snow levels in higher terrain)
Ability to classify precipitation type
New severe thunderstorm signatures
The full benefit of dual-pol radar, however, will not be fully realized until NWS forecasters and research meteorologists develop real-time expertise.
What is polarization?
A radio wave is a set of oscillating electric and magnetic fields, oriented 90 degrees to each other. Polarization
of the wave is the direction, or orientation, of the electric field.
Horizontal Polarization
The electric field is oriented horizontally, along the x-axis (blue). The magnetic field is oriented vertically along the y-axis (white).
Vertical Polarization
The electric field is oriented vertically, along the y-axis (orange). The magnetic field is oriented horizontally along the x-axis (white).
Current NWS Doppler Radar (horizontally-polarized only)
Current Doppler radar capability transmits and receives only horizontally polarized radio wave pulses. Therefore, they
measure only the horizontal dimension of cloud and precipitation particles.
"Dual Polarized" Radar
New dual-pol capability will allow the transmit and receipt of both horizontally and vertically polarized radio wave pulses. Therefore, they
measure both the horizontal and vertical dimension of cloud and precipitation particles.
More Information
Dual-Polarization Training for NWS Partners
National Severe Storms Laboratory Dual-Pol Page
National Severe Storms Laboratory Dual-Pol FAQ Page
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