Radiative Impacts of Misclassification of Cloud Thermodynamic Phase

Cloud thermodynamic phase is one cloud observation among a set necessary to monitoring cloud-climate feedbacks. Together with cloud height, temperature, thermodynamic phase,and optical properties such as effective radius and optical thickness, cloud phase is necessary to model the radiative impacts of clouds. While much progress has been made in recent years in satellite-based cloud phase determination using near-infrared measurements of reflected solar radiation, most infrared-based techniques still rely on a priori assumptions of relationships between cloud phase and cloud temperature. We will present a new method for retrieving cloud phase using infrared satellite observations from the MODIS and AIRS instruments. This method does not depend on an assumed relationship between cloud phase and temperature, making it useful for studying potentially mixed-phase clouds with temperatures between 255 and 265 K. This method will be applied to several case studies using MODIS and AIRS data, allowing relationships between cloud phase, height, and temperature to be determined. These relationships will be used as input to a broadband radiative transfer model to address the following question: "What are the radiative impacts of misclassification of cloud thermodynamic phase?" In particular, we will address the effects of redistributing water vertically and between phases. For each set of relationships, longwave and shortwave cloud forcing will be calculated at the surface of the earth, the top of the atmosphere, and the atmospheric layers in between.