wsacr2cfrcrras (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.

大气辐射测量（ARM）计划的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。每座天线座架均配备一台Ka波段雷达（峰值功率2kW），部署场地将决定第二台雷达的频段：若为W波段，则为WSACR（峰值功率1.7kW）；若为X波段，则为XSACR（峰值功率20kW）。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扫描云雷达采用与常规天气雷达迥异的扫描策略。其并未采用主流的平面位置指示器（plan position indicator, PPI）扫描模式，Ka波段扫描云雷达（Ka-SACR）会在多个方位角上执行距离高度指示器（range height indicator, RHI）扫描，以获取云体三维体积数据。W波段扫描云雷达（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、谱宽以及非扫描时段的频谱，还有线性退极化比。