On the Forward Modeling of Radar Doppler Spectrum Width From LES: Implications for Model Evaluation Journal Article uri icon



  • AbstractLarge‐eddy simulations of an observed single‐layer Arctic mixed‐phase cloud are analyzed to study the value of forward modeling of profiling millimeter wave cloud radar Doppler spectral width for model evaluation. Individual broadening terms and their uncertainties are quantified for the observed spectral width and compared to modeled broadening terms. Modeled turbulent broadening is narrower than the observed values when the turbulent kinetic energy dissipation rate from the subgrid scale model is used in the forward model. The total dissipation rates, estimated with the subgrid scale dissipation rates and the numerical dissipation rates, agree much better with both the retrieved dissipation rates and those inferred from the power spectra of the simulated vertical air velocity. The comparison of the microphysical broadening provides another evaluative measure of the ice properties in the simulation. To accurately retrieve dissipation rates as well as each broadening term from the observations, we suggest a few modifications to previously presented techniques. First, we show that the inertial subrange spectrum filtered with the radar sampling volume is a better underlying model than the unfiltered −5/3 law for the retrieval of the dissipation rate from the power spectra of the mean Doppler velocity. Second, we demonstrate that it is important to filter out turbulence and remove the layer‐mean reflectivity‐weighted mean fall speed from the observed mean Doppler velocity to avoid overestimation of shear broadening. Finally, we provide a method to quantify the uncertainty in the retrieved dissipation rates, which eventually propagates to the uncertainty in the microphysical broadening.

publication date

  • July 27, 2018

has restriction

  • bronze

Date in CU Experts

  • December 25, 2021 12:22 PM

Full Author List

  • Chen Y; Verlinde J; Clothiaux EE; Ackerman AS; Fridlind AM; Chamecki M; Kollias P; Kirkpatrick MP; Chen B; Yu G

author count

  • 11

Other Profiles

International Standard Serial Number (ISSN)

  • 2169-897X

Electronic International Standard Serial Number (EISSN)

  • 2169-8996

Additional Document Info

start page

  • 7444

end page

  • 7461


  • 123


  • 14