Recently, solid-state power amplifier (SSPA) is used in X-band polarimetric weather radar due to the precise waveform, mobility, longevity, and maintainability. However, SSPA X-band radar shows an inherent weakness of low sensitivity due to relative low peak power (less than 200W). Therefore, SSPA X-band radar transmits long-pulse to obtain sufficient sensitivity. This type of pulse brings two problems (mainly): 1) decrease of range resolution, 2) blind-zone region near the radar due to transmitting time. To mitigate decreasing of range resolution problem, pulse compression technique is used with wide frequency technique. To mitigate blind-zone, multiple pulses (short pulse is transmitted at end stage of pulse transmitting) are used. However, short pulse has different sensitivity with long pulse. This different observation characteristic brings discontinuity of polarimetric measurements along radial direction and discontinuity of polarimetric measurements is one of the main issues in solid-state X-band radar utilization.
In this study, the PX-1000 radar developed by the Advanced Radar Research Center (ARRC) in University of Oklahoma is used. We investigate potential utilization of polarimetric rainfall estimation along the discontinuity of SSPA X-band radar using measured and retrieved polarimetric variables images (PPI, A-scope, the quasi-vertical profile (QVP) of polarimetric measurements). For estimation of polarimetic rainfall, the attenuation and bias corrected reflectivity (Z), specific attenuation (AH) and the proxy of specific differential phase (KDP) are used. The rainfall estimation results of different microphysical processes are compared with rain gauges.
Acknowledgment
This research was supported by a grant (17AWMP-B079625-04) from Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.
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