National Weather Service Miami WSR-88D to Receive Dual Polarization Upgrade
During a two-week period, beginning January 30, 2012 and ending February 12, 2012, the Doppler radar at the National Weather Service Forecast office in Miami, Florida, will undergo an upgrade to incorporate new technology.
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.
The electric field is oriented horizontally, along the x-axis (blue). The magnetic field is oriented vertically along the y-axis (white).
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.