Cloud Processes Group

Mixed-phase stratiform clouds are ubiquitous in the Arctic and have a large impact on Arctic energy balance. They are a challenge to understand as they contain a mix of ice and supercooled water that—despite freezing temperatures—remain liquid and can persist for long periods of time, even while steadily losing ice particles through precipitation.  Their maintenance results from the feedbacks between numerous local processes that greatly complicate their understanding and modeling.

BNL researchers work to understand the properties (e.g., liquid vs. ice phase, ice particle habit) and processes (e.g. deposition, aggregation, riming, break-up) involved in the evolution of these clouds and their impacts on the Arctic, focusing on the following topics.

• Develop the next generation of snow/ice microphysical retrievals to determine properties of the ice and supercooled water using new ARM cloud radar measurements that are multi-frequency and fully polarimetric;
• Use these observations to improve process-level understanding by studying pathways for the development of ice in mixed-phase clouds by characterizing and quantifying the processes involved in the cloud evolution;
• Quantify the radiative impacts of mixed-phase clouds on the Arctic energy budget.