Articles | Volume 8, issue 8
Atmos. Meas. Tech., 8, 3493–3517, 2015
Atmos. Meas. Tech., 8, 3493–3517, 2015

Research article 26 Aug 2015

Research article | 26 Aug 2015

Performance assessment of a triple-frequency spaceborne cloud–precipitation radar concept using a global cloud-resolving model

J. Leinonen1, M. D. Lebsock1, S. Tanelli1, K. Suzuki1,3, H. Yashiro2, and Y. Miyamoto2 J. Leinonen et al.
  • 1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
  • 2RIKEN Advanced Institute for Computational Sciences, Kobe, Japan
  • 3Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan

Abstract. Multi-frequency radars offer enhanced detection of clouds and precipitation compared to single-frequency systems, and are able to make more accurate retrievals when several frequencies are available simultaneously. An evaluation of a spaceborne three-frequency Ku-/Ka-/W-band radar system is presented in this study, based on modeling radar reflectivities from the results of a global cloud-resolving model with a 875 m grid spacing. To produce the reflectivities, a scattering model has been developed for each of the hydrometeor types produced by the model, as well as for melting snow. The effects of attenuation and multiple scattering on the radar signal are modeled using a radiative transfer model, while nonuniform beam filling is reproduced with spatial averaging. The combined effects of these are then quantified both globally and in six localized case studies. Two different orbital scenarios using the same radar are compared. Overall, based on the results, it is expected that the proposed radar would detect a high-quality signal in most clouds and precipitation. The main exceptions are the thinnest clouds that are below the detection threshold of the W-band channel, and at the opposite end of the scale, heavy convective rainfall where a combination of attenuation, multiple scattering and nonuniform beam filling commonly cause significant deterioration of the signal; thus, while the latter can be generally detected, the quality of the retrievals is likely to be degraded.

Short summary
Using multiple frequencies in cloud and precipitation radars enables them to be both sensitive enough to detect thin clouds and to penetrate heavy precipitation, profiling the entire vertical structure of the atmospheric component of the water cycle. Here, we evaluate the performance of a potential future three-frequency space-based radar system by simulating its observations using data from a high-resolution global atmospheric model.