Beam Matching of the Dual-Frequency Precipitation Radar Onboard the Global Precipitation Measurement Core Observatory.

Beam matching accuracy between KuPR and KaPR was evaluated by external calibration using ARC. The averaged distance between the beam centers of KuPR and KaPR is 318 m for Rx and 269 m for Tx before the beam matching parameters were changed. After the change, the distance is 92 m for Rx and 85 m for Tx. The distance between the beam matched footprints of KuPR and KaPR during normal observation were confirmed using the geolocation. In the inner swath, the averaged distance before and after the scan pattern change is 140 m and 32 m, respectively. In the outer swath of KuPR angle-bin number 38 to 49 after the scan pattern change, the averaged distance is 48 m. However, the KuPR beams at angle-bin number 1 to 12 are slightly shifted from the corresponding KaHS beams in the along-track direction. The magnitude of misalignment is 301 m.