NorthPol History

The University of North Dakota weather radar is a 5-cm wavelength weather radar manufactured by Enterprise Electronics Corporation. It was acquired by the Department of Aviation in 1974 through funding from the NSF for the purpose of weather modification research and training. This radar system was the seed for meteorological research at UND that has led to $45 million in funded research over the years. From 1975 through 1993 it was utilized primarily as a mobile facility and was deployed in various research programs at locations as far away as Utah and Florida. Initially, the radar was deployed in support of the Bureau of Reclamation's Project Skywater, a program designed to develop a precipitation increase technology.

The first major upgrade to the system occurred in the mid-1980s when UND became involved, through the Federal Aviation Administration (FAA), in an interagency effort to modernize the national weather radar network. At that time a Doppler velocity measurement capability was added along with a new, larger antenna. The FAA work expanded to support an effort to apply Doppler radar technology to the detection of low-level windshear and microburst hazards in the vicinity of airports. That program resulted in the deployment of nearly 50 Terminal Doppler Weather Radars at major airports across the country.

Outside of these major federal programs the UND radar also participated in a number of other scientific experiments jointly funded by the NSF, the Bureau of Reclamation, and the National Oceanic and Atmospheric Administration. These included the Cooperative Convective Precipitation Experiment, the North Dakota Thunderstorm Project, and the North Dakota Tracer Experiment. Since 1993 the radar has been located on top of Clifford Hall at the west end of the UND campus and has been operated in support of the academic programs of the Department of Atmospheric Sciences.

The original components of the UND C-Band Doppler radar were built by Enterprise Electronics Corporation (model: Weather Surveillance Radar - 1974; C-band: WSR-74C). In the 1980s the radar system was upgraded to provide Doppler velocity capability. The upgrade included the installation of a pulse-pair signal processor, radar color display unit, radar controller interface, and analog receiver that were built by SIGMET Corporation. The radar was controlled by an HP1000 model workstation that was built in the early 1980s.

January 2003 Upgrades

The department acquired funding through the support of UND to modernize the radar back to research quality. The Atmospheric Sciences department was awarded a Student Technology Fee grant to upgrade the radar processing and display software. Also, through the support of the Vice President for Academic Affairs (VPAA) office and the Dean's Office in the Odegard School of Aerospace Sciences money was acquired to install modern radar hardware and a new computer system. This upgrade occurred in late January 2003. The new system was developed by SIGMET, which provides seamless integration of the new technology with their existing system. The upgrade included the following:

• RVP8 digital receiver and signal processor with 14-bit IF Digitizer
  • RCP8 radar antenna controller with custom connector panel for existing cables
  • Interactive Radar Information System (IRIS) radar control, analysis, and display software
• Two high-speed data PC-based LINUX workstations with a massive disk storage device

The upgrade allowed us to obtain precise measurements of horizontal radar reflectivity, meaning Doppler velocity, and Doppler spectrum width. The IRIS radar software has the capability of generating a wide variety of research-quality radar-derived products. Data, products, and real-time display can be sent across the network to remote computers. This provides a valuable tool for the distribution of information across campus for activities such as classroom teaching.

January 2004 Upgrades

This upgrade brought the radar to the national trend, which is the progression towards polarimetric capability. To be competitive in research activities and provide students the opportunity to train with the latest technology we upgraded the UND radar to have polarimetric capability in January 2004. SIGMET has developed an Antenna Mounted Receiver (AMR) that allows us to have dual-polarization capability at the fraction of the cost of purchasing a new polarimetric radar. SIGMET integrated the polarimetric radar and software components with the earlier upgrades. The upgrade included the following components:

• Modification of UND radar antenna to allow transmitting and receiving of both polarizations
• Installation of antenna mounted receiver (AMR)
• IRIS software upgrades to support polarimetric variables

A new dual-feedhorn and waveguide system was installed on the antenna along with the modification of the antenna and pedestal for the AMR. Two digital receivers integrated into the AMR allows us to transmit and receive horizontal and vertical polarized signals. The IRIS software upgrade provides the ability to process and display the polarimetric radar observables. Besides collecting the traditional fields of radar reflectivity, mean Doppler velocity, and Doppler spectrum width, the radar provides observations of differential reflectivity, depolarization ratio, the phase, and correlation between the horizontal and vertical channels. The IRIS analysis software is capable of producing over 15 NEXRAD-type products in real-time and post-processing. It has the flexibility to add user specified algorithms. This will provide detailed characteristics about radar targets that are not available with most radars.

Projects