Design and deployment of quickly scanning dual-frequency, dual-polarization, dual-Doppler mobile radar network

Given the need to simultaneously measure rapidly evolving weather phenomena as well as characterize the microphysical properties, the Center for Severe Weather Research (CSWR) in close collaboration with the University of Colorado (CU) have upgraded both single-beam Doppler on Wheels radars (DOWs) to a new dual-polarization design that permits fast, full dual-polarization and very fast 45-degree transmit polarization modes through the use of two transmitters in each radar. The dual transmitter approach permitted the full spectrum of polarimetric measurements, which include ZH, ZV, ZDR, Rho-HV, Phi-DP, and LDR, without the need for a polarization switch, with the added advantage of two transmit frequencies. In double-speed polarization scanning mode, the two transmitters, which operate at frequencies separated by 150 MHz, permit doubled independent sampling for both velocity and 45-degree dual-polarization products such as ZDR, Phi-DP, and Rho-HV, thereby allowing for doubled scan rates. In an alternate mode, one frequency can transmit at 45 degrees, receiving H and V simultaneously, measuring ZDR, Phi-DP, and Rho-HV, while the other transmitter transmits H and receives H and V simultaneously, measuring, among other products, LDR. With this design, the new systems will be the only mobile radars that simultaneously measure LDR, Rho-HV, Phi-DP, and ZDR simultaneously. Initial results from the first deployments in VORTEX2-2010 will be shown.