Doppler Velocity Observations with the EarthCARE Radar
Battaglia, Alessandro1; Kollias, Pavlos2; Tanelli, Simone3; Ohno, Y.4
1Earth Observation Sciences, Department of Physics and Astronomy, University of Leicester, UNITED KINGDOM; 2Department of Atmospheric and Oceanic Science, McGill University, Montreal, QC, CANADA; 3Jet Propulsion Laboratory, Pasadena, California, UNITED STATES; 4National Institute of Information and Communications Technology
The 94 GHz Cloud Profiling Radar onboard the ESA/JAXA EarthCARE mission will be the first radar in space with Doppler capability allowing mean Doppler velocity measurements. It is the only instrument of this kind planned for the immediate post-CloudSat era and it is expected to provide unprecedented global coverage of vertical-velocity field distribution in clouds and a better characterization of dynamic energy transfers in the Earth's atmosphere. In this work, we discuss the parameters that influence the performance of the CPR Doppler measurements in cirrus clouds, large-scale precipitation and in convective scenarios as derived from notional simulations. The input to our simulations consists either of actual atmospheric W-band Doppler measurements or cloud resolving model hydrometeor profiles. Several corrections are then applied to account for the spacecraft motion, the space-borne antenna characteristics and the horizontal and vertical resolution of the EarthCARE CPR. Further, the effects of random fluctuations and noise are included. Noise, Doppler aliasing, non-uniform beam filling and multiple scattering affect the radar Doppler estimates differently in different cloud scenarios. In addition to highlighting the expected performance of CPR in various cloud scenarios and at different integration length, we will show corrections and flagging procedures that are planned for ground processing the CPR data to recover the mean-Doppler velocity, particularly in the presence of aliasing, non-uniform beam-filling and multiple scattering contaminations.