Polar-WRF evaluation at Siple Dome in West Antarctica: Fidelity of a double-moment mixed-phase cloud parameterization via surface irradiance measurements
AbstractAbstract
A set of surface energy balance observations from Siple Dome in West Antarctica, combined with all-sky imagery and spectral shortwave irradiance data, provide a unique resource for evaluating atmospheric model performance with current mixed-phase cloud microphysical parameterizations. This location is in a region of current concern regarding atmospheric surface melting stress on ice shelves. The Polar Weather Research and Forecasting (PWRF) version 4.7.1, equipped with the Thompson aerosol-aware double-moment parameterization, is initialized with ERA5 reanalysis data to simulate hourly surface radiative flux components and cloud microphysical properties matching observations spanning 21 December 2019 to 19 January 2020. Consistent with earlier studies, the double-moment scheme improves cloud amount, net longwave, and net radiative flux simulations compared with the ERA5 single-moment scheme. However, PWRF with the double-moment scheme produces simulations that are episodic in their realism compared with all available observations. Instances of good agreement, for example within 20 W m
−2
in radiative fluxes, alternate with days showing larger discrepancies. Additionally, PWRF produces excessive cloud liquid water during a modest storm system intrusion, but inadequate cloud liquid and ice water during quiescent conditions when low-level stratus clouds show phase transitions due to precipitation. These results illustrate the value of Siple Dome as a site for fundamental studies in mixed-phase cloud microphysics.
