Mesoscale Dynamics and Mixed-phase Microphysics in Arctic Cold Air Outbreaks

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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. A unique aspect of this award is the mentorship of a student in the NCAR Significant Opportunities in Atmospheric Research and Science (SOARS) program, which is an undergraduate-to-graduate bridge program designed to broaden participation of historically underrepresented communities in atmospheric and related science. This project will contribute to the overall CAESAR goals by focusing on the finely resolved vertical transects of precipitation and kinematic data from airborne Doppler radars, and in situ cloud and precipitation probes. The scientific objectives of this award are to: 1) to characterize the vertical structure and circulations of Marine Boundary Layer (MBL) convection in cold-air outbreaks (CAOs), in order to elucidate the role of cloud processes in the mesoscale organization of the CAO cloud regime, and in polar lows; and 2) to document the size and phase distribution of hydrometeors, in order to elucidate the roles of primary and secondary ice processes on precipitation generation and cloud dynamics. The team will be responsible for installing and test-flying the Ka-band Precipitation Radar (KPR), developing an improved Wyoming Cloud Radar (WCR) hydrometeor vertical velocity profile dataset, developing the QA/QC’d and processed KPR reflectivity and Doppler velocity dataset, developing the WCR dual-Doppler velocity synthesis dataset, providing the retrieval of Ice Water Content (IWC) and other cloud and precipitation products from WCR and other sensors, and providing in-situ Liquid Water Content (LWC)/IWC from the Nevzorov probe.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.