Realization of the NASA Dual-Frequency Dual-Polarized Doppler Radar (D3R)

Author(s):  
Manuel Vega ◽  
James Carswell ◽  
V. Chandrasekar ◽  
Mathew Schwaller ◽  
Kumar Vijay Mishra
Radio Science ◽  
2014 ◽  
Vol 49 (11) ◽  
pp. 1087-1105 ◽  
Author(s):  
Manuel A. Vega ◽  
V. Chandrasekar ◽  
James Carswell ◽  
Robert M. Beauchamp ◽  
Mathew R. Schwaller ◽  
...  

2015 ◽  
Vol 32 (4) ◽  
pp. 767-782 ◽  
Author(s):  
Cuong M. Nguyen ◽  
V. Chandrasekar

AbstractThis paper presents a procedure to filter ground clutter from dual-polarized staggered pulse repetition time (PRT) radar data in simultaneous and alternating transmission modes for polarimetric variables retrieval. The filter is designed in the time domain so that polarimetric variables such as the differential phase () and the copolar correlation coefficient () can be estimated directly from clutter-filtered time series data using a conventional method. In the case of the simultaneous mode, a single filter is used for both channels to maintain the signal correlation after filtering. For the alternating mode, because the polarizations are transmitted in different waveforms, two separate filters are required. However, the filters are designed so that the responses of the filters to the signals are identical within the extended Doppler range. Based on radar simulation, it is shown that the method can provide accurate retrieval of polarimetric variables even in the case of strong clutter contamination. Also, the performance of the method is illustrated on dual-polarized staggered PRT ⅔ data from the NASA dual-frequency dual-polarized Doppler radar (D3R).


Author(s):  
Manuel A. Vega ◽  
V. Chandrasekar ◽  
Cuong Nguyen ◽  
Kumar Vijay Mishra ◽  
James Carswell

2018 ◽  
Vol 99 (6) ◽  
pp. 1177-1195 ◽  
Author(s):  
Nicholas McCarthy ◽  
Hamish McGowan ◽  
Adrien Guyot ◽  
Andrew Dowdy

AbstractThe process of pyroconvection occurs when fire-released heat, moisture, and/or aerosols induce or augment convection in the atmosphere. Prediction of pyroconvection presents a set of complex problems for meteorologists and wildfire managers. In particular, the turbulent characteristics of a pyroconvective plume exert bidirectional feedback on fire behavior, often with resulting severe impacts on life and property. Here, we present the motivation, field strategy, and initial results from the Bushfire Convective Plume Experiment, which through the use of mobile radar aims to quantify the kinematics of pyroconvection and its role in fire behavior. The case studies presented include world-first observations from two wildfires and one prescribed burn using the University of Queensland’s portable, dual-polarized X-band Doppler radar (UQ-XPOL). The initial analyses of reflectivity, Doppler winds, polarimetric variables, and spectrum width data provide insights into these relatively unexplored datasets within the context of pyroconvection. Weather radar data are supported by mesonet observations, time-lapse photography, airborne multispectral imaging, and spot-fire mapping. The ability to combine ground-validated fire intensity and progression at an hourly scale with quantitative data documenting the evolution of the convective plume kinematics at the scale of hundreds of meters represents a new capability for advancing our understanding of wildfires. The results demonstrate the suitability of portable, dual-polarized X-band Doppler radar to investigate pyroconvection and associated plume dynamics.


2016 ◽  
Vol 8 (6) ◽  
pp. 963-972 ◽  
Author(s):  
Benjamin Rohrdantz ◽  
Thomas Jaschke ◽  
Frauke K. H. Gellersen ◽  
Anton Sieganschin ◽  
Arne F. Jacob

In this contribution a dual-band, dual-polarized microstrip antenna element for array applications is presented. The patch antenna is designed to operate simultaneously at around 30 and 20 GHz, the up- and downlink frequencies of modern Ka-band satellite communication systems. The antenna is smaller than half the freespace wavelength at 30 GHz to enable its utilization as array element of dual-band ground terminals. Integrating transmitter and receiver circuits allows, in turn, for a very compact active terminal solution. To minimize production cost, the design is carried out in standard multilayer printed circuit board technology. The antenna features two distinct polarization ports suitable for either dual linear or dual circular polarization if both ports are excited in quadrature. The single antenna design process is described in detail and simulation and measurement results are presented. Finally, different arrays based on this patch antenna are evaluated by simulation and measurements.


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