Current status of GPM/DPR level 1 algorithm development and DPR calibration

This paper describes current status of the level 1 algorithm development and calibration for the Dual-frequency Precipitation Radar (DPR) onboard the Global Precipitation Measurement (GPM). JAXA has carried out the calibration for the DPR since the GPM core observatory was launched on February 28, 2014 (JST). As a result of the external calibration, it is detected that some biases seemed to exist. However, JAXA has not adjusted the calibration coefficient of the DPR level 1 algorithm because of two reasons. One is the errors of the external calibration. In the external calibration, the measurement error and estimation error for the power may occur. The other reason is the continuity of the surface backscattering cross section (denoted as σ⁰) from Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR). Requirement of the continuity has been satisfied by using the current calibration coefficient.