Study the seasonal and interannual variations of mixed-phase cloud properties based on the observations from the ARM Northern Slope Alaska site

Mixed-phase clouds play a particularly important role in the Arctic climate system. A multiple sensor algorithm was developed to study arctic mixed-phase clouds. However, the algorithm only can be applied to clouds with infrared absorption optical depth smaller than 3. A new approach to retrieve more reliable liquid water path (LWP) based on microwave radiometer (MWR) measurements is developed, which allow us to combine MWR LWP retrievals with the multiple remote sensor retrievals to analyze all arctic mixed-phase clouds. Based on the long-term ARM Northern Slope Alaska (NSA) observations, we are able to characterize the seasonal and interannual variations of arctic mixed-phase cloud macro- and micro-physical properties. The paper will present a comprehensive arctic mixed-phase cloud picture at the NSA site in terms of the occurrence and temperature and vertical distributions of arctic mixed-phase clouds, the frequency distributions and temperature dependencies of ice and water optical depths and particle sizes, and the temperature dependency of ice and water optical depth ratio. An accurate documentation of arctic mixed-phase cloud macro- and micro-physical properties is a critical step to advance our understanding of them.