Arctic Cold-Air Outbreak Mixed-Phase Cloud Characteristics, Processes and Impacts in Observations and Models

University Of Miami, Coral Gables FL

Investigators

Abstract

Arctic climate is changing at a faster pace than anywhere on Earth. Climate projections indicate that the Arctic will continue to warm, but uncertainties arise due to questions about the future behavior of Arctic clouds. An area of primary uncertainty is the properties of clouds that form during cold-air outbreaks, where very cold airmasses over the Arctic ice move southward over the relatively warm open ocean. This award will help to provide observational data of these clouds (and precipitation) and the exchange of energy between the ocean and atmosphere during the Cold-Air outbreak Experiment in the Sub-Arctic Region (CAESAR), which will be conducted in Spring 2024 out of northern Scandinavia. The observations collected during CAESAR will be used in an effort to better understand the characteristics of the cold-air outbreak system, and the Arctic climate system more broadly, in order to inform climate models and projections. The project will also help to improve forecasting of weather hazards with significant relevance to naval operations, commercial shipping, and coastal communities. The broader field effort includes significant opportunities for students and early-career scientists, international collaboration, and public outreach. This award will contribute to the main broader impact goals of the CAESAR campaign. This project will make use of remote sensing observations of mixed-phase clouds to characterize their partitioning between liquid and ice as a function of the cloud evolution, with an additional step of using CAESAR-constrained large-eddy-scale simulations to understand the processes that determine this partitioning. The primary addition to the CAESAR campaign from this award is the measurement of cloud liquid water path from a G-band Vapor Radiometer. The researchers hypothesize that the cold air outbreak clouds produced near the sea ice edge are fully liquid, and transition to liquid cloud overlying ice precipitation further downstream, through interactions with the large-scale environmental parameters (aerosol and dynamical) that are reflected in the cloud morphology. A counter-hypothesis is that much of the precipitation can also occur as super-cooled drizzle, potentially due to a lack of ice nucleating particles (INPs). Primary funding for this project comes from the Physical and Dynamic Meteorology program with partial funding from the Arctic Natural Sciences program. The deployment of observational assets for CAESAR is being funded by the Facilities for Atmospheric Research and Education program. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.