The Microwave Snow Scattering Signature: Precipitation Regime Dependence

All-weather data assimilation of passive microwave observations requires forward modeling tools that accurately characterize interaction of multi-frequency microwave radiation with frozen hydrometeors. This study adopts a combined observational and modeling approach to investigate possible systematic differences in the microwave ice scattering signature in cold-season precipitation events over the North Atlantic Ocean. A multi-year CloudSat/AMSR-E database is partitioned between different precipitation regimes, and the observed high-frequency scattering signature is assessed for systematic differences between precipitation types. Preliminary observational findings indicate a systematic lack of scattering signal in shallow, convective snowfall events compared to deeper, synoptically forced snowfall events in this region. Radiative transfer (RT) simulations will be undertaken using ice models as proxies for frozen hydrometeors in a radiative closure and RT assessment exercise for the different precipitation regimes identified in the observational component of this study. This study will highlight the potential for using passive microwave observations in future data assimilation schemes for high-latitude precipitation events, as well as the inherent complexities of properly modeling these events from a multi-frequency microwave perspective.