wsacrcrrhi (a1)

ARM's scanning cloud radars are fully coherent dual-frequency, dual-polarization Doppler radars mounted on a common scanning pedestal. Each pedestal includes a Ka-band radar (2kW peak power) and the deployment location determines whether the second radar is a W-band (WSACR; 1.7 kW peak power) or X-band (XSACR; 20 kW peak power). Beamwidths at Ka and W bands are roughly matched at 0.3 degrees. Due to the narrow antenna beamwidth, ARM’s scanning cloud radars use scanning strategies that are unlike typical weather radars. Rather than focusing on plan position indicator, or PPI, scans, the Ka-SACR uses range height indicator, or RHI, scans at numerous azimuths to obtain cloud volume data. Measurements collected with the W-SACR are copolar and cross-polar radar reflectivity, Doppler velocity, spectra width and spectra when not scanning, and linear depolarization ration.

ARM扫描云雷达为全相干双频双偏振多普勒雷达，搭载于统一的扫描天线座架。每台座架均配备一台Ka波段雷达（峰值功率2 kW），根据部署场地的不同，第二台雷达可选配W波段雷达（WSACR，峰值功率1.7 kW）或X波段雷达（XSACR，峰值功率20 kW）。Ka波段与W波段的波束宽度大致匹配，均为0.3度。由于天线波束宽度极窄，ARM扫描云雷达采用的扫描策略与典型气象雷达存在显著差异。Ka波段SACR并未采用常规的平面位置指示（plan position indicator，简称PPI）扫描模式，而是通过在多个方位角下执行距离高度指示（range height indicator，简称RHI）扫描，以获取云体三维体积数据。W-SACR的观测参数包括同极化与交叉极化雷达反射率、多普勒速度、非扫描状态下的谱宽与频谱，以及线性退极化比。