Local WSR-88D Radars to Receive Dual Polarization Upgrade

Picture of WSR-88D Radar

Each of the Doppler radars in our area will be upgraded, which will take up to a two-week period.

 - Paducah WSR-88D - Complete

 - Fort Campbell WSR-88D - On-going

- Owensville (Evansville) WSR-88D - Beginning on or around February 4, 2013

For up to 2 weeks, each radar will be unavailalble starting at the

dates listed above to undergo an upgrade to incorporate new technology.

Surrounding radars include: Springfield, MO, St. Louis, MO, Central Illinois,

Indianapolis, IN, Owensville (Evansville), IN, Louisville, KY, Fort Campbell, KY,

Nashville, TN, and Memphis, TN.

This much anticipated upgrade is part the NWS vision to build a

Weather-Ready Nation to better protect lives and livelihoods. This

exciting upgrade will incorporate a new technology called dual-

polarization, or dual-pol. This new technology will result in 14 new

radar products that will enable us to continue improving our suite

of high quality products and services to the public. This new

technology and data will primarily help forecasters identify the type

of precipitation that is falling, as well as improve rainfall estimates.

Why Upgrade to Dual-Pol?

Current NWS Doppler radars transmit and receive pulses of radio waves

in a horizontal orientation. As a result, the radar only measures the

horizontal dimensions of targets (e.g., cloud and precipitation droplets).

Dual-polarimetric radar transmits and receives pulses in both a

horizontal and vertical orientation. Therefore, the radar measures

both the horizontal and vertical dimensions of targets. Since the radar

receives energy from horizontal and vertical pulses, we can obtain

better estimates of the size, shape, and variety of targets. It is

expected that this will result in significant improvements in the

estimation of precipitation rates, the ability to discriminate between

precipitation types (e.g., hail vs. rain), and the identification of

non-meteorological returns, such as chaff, ground clutter, and smoke

plumes from wildfires that are not uncommonly detected by weather radar

systems such as WSR-88D.


Current NWS Doppler RadarDual-Pol Radar                                   
The Benefits of Dual-Pol

- Better estimation of total precipitation amounts

- Better estimation of size distribution of hydrometeors

- Much improved ability to identify areas of heavy

rainfall that are closely linked to flash floods

- Improved detection and mitigation of non-weather

related radar echoes (chaff, smoke plumes, ground clutter)

- Easier identification of the melting layer

(helpful for identifying snow levels in higher terrain)

- Improved ability to classify precipitation type

The full benefit of dual-pol radar, however, will not be fully realized until

NWS forecasters and research meteorologists develop real-time



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

Horizontal Polarization Graph

The electric field is oriented horizontally, along the x-axis (blue).

The magnetic field is oriented vertically, along the y-axis (white).

Vertical Polarization


Vertical Polarization Graph

The electric field is oriented veritically, along the y-axis (orange).

The magnetic field is oriented horizontally, along the x-axis (white).

Want to Learn More?

Dual-Polarization Training for NWS Partners

National Severe Storms Laboratory Dual-Pol Page

National Severe Storms Laboratory Dual-Pol FAQ Page




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.