Evaluation of Radar Multiple-Scattering Effects from a GPM Perspective. Part II: Model Results

Abstract

Multiple-scattering effects as sensed by radars in configurations useful in the context of the Global Precipitation Mission (GPM) are evaluated for a range of meteorological profiles extracted from four different cloud-resolving model simulations. The multiple-scattering effects are characterized in terms of both the reflectivity enhancement and the linear depolarization ratio. When considering the copolarized reflectivity in spaceborne configurations, the multiple-scattering enhancement becomes a real issue for Ka-band radars, though it is generally negligible at the Ku band, except in meteorologically important situations such as when high rain rates and a considerable amount of ice are present aloft. At Ka band it can reach tens of decibels when systems of heavy cold rain are considered, that is, profiles that include rain layers with high-density ice particles aloft. On the other hand, particularly at 35 GHz, high values of the linear depolarization ratio are predicted even in airborne configurations because of multiple-scattering effects. This result should allow the observation of these features in field campaigns.