CAESAR: Characterizing and Understanding Atmospheric Boundary Layer Fluxes, Structure and Cloud Property Evolution in Arctic Cold Air Outbreaks

Suny At Stony Brook, Stony Brook NY

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 to better understand the characteristics of the cold-air outbreak system, and the Arctic climate system more broadly, 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 specific project includes a training component for senior level undergraduate students on field methods and observations that will parallel the planning and execution of the CAESAR campaign. This goal of this project is to use multiple remote sensor and in-situ measurements to (1) characterize Marine Boundary Layer (MBL) fluxes, structure and cloud properties and (2) understand the process controlling the evolution of MBL fluxes, structures and cloud properties during cold-air outbreaks (CAOs). The research team will deploy the Multi-function Airborne Raman Lidar (MARLi) and the nadir-only Airborne Doppler Lidar (ADL) to provide profiles of water vapor, temperature, air vertical velocity, and aerosol/cloud structure below the NSF/NCAR C-130 research aircraft to document MBL thermodynamic and dynamic structures, mixing across the MBL top, and cloud phase and property distributions. Analysis of MARLi and ADL data, combined with other observations and modeling during CAESAR, will allow the team to focus on understanding of how upstream boundary layer stratification and wind, MBL rolls and small-scale vertical motions, and surface fluxes and Atmospheric Boundary Layer (ABL) top entrainment/mixing controls MBL development and evolution during CAOs. In addition, these measurements will address the question of how aerosol, MBL processes, and cloud dynamics (stratiform and convective clouds) impact mixed-phase cloud properties, especially liquid-ice mass partitioning. 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.