Drivers and Impacts of North Atlantic freshwater and heat fluxes unsettling modern-day climate (DIMSUM)

University Of Texas At Austin, Austin TX

Investigators

Abstract

This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries. Exchanges between the Arctic and North Atlantic (NA) of heat and freshwater (FW) impact the large-scale NA and global climate. The complex interactions and feedbacks span many spatial and temporal scales from short-term and local to multi-decadal and across ocean basins. An accurate understanding of the mechanisms impacting heat and FW fluxes into the NA, and subsequent ocean mixing that sets surface properties, is therefore of critical importance for assessing the risks of rapid NA climate change. This project will use a comprehensive set of observation- and model-based products and tools to significantly advance our understanding of NA heat and FW variations, elucidating drivers, exposing atmospheric feedbacks, and exploring subsequent impacts on larger-scale weather and climate. Understanding the intricate relationship between climate change and weather patterns is of paramount societal significance. This project plays a pivotal role in addressing this challenge by shedding light on the behavior of a major, yet uncertain, component within the system, ultimately contributing to more informed climate adaptation and mitigation strategies. The research team features a high proportion of female scientists and two PIs (Lenn & Nguyen) from historically-under-represented global south ethnic groups in geosciences. The project provides training and leadership opportunities for early-career female scientists Pillar and Schulz (UT Austin). This project will investigate drivers and impacts of heat and FW changes in the NA by capitalizing on a comprehensive set of observation- and model-based products and tools, in particular the OSNAP and RAPID mooring arrays, coupled high-resolution model simulations, and the Arctic Subpolar gyre sTate Estimate (ASTE). ASTE, a dynamically consistent model-data synthesis with inbuilt adjoint capability, provides a very unique and powerful tool for investigation of causal drivers of NA dynamics and variability. Combining these products with novel statistical tools and state-of-the-art analysis techniques, will help the assess mechanisms of change up- and downstream of the arrays and evaluate their climate feedbacks, including potential drivers and impacts of a rapid Beaufort Gyre FW release. The three research objectives of the project are (O1) Quantify heat and FW budgets, using observations (e.g., OSNAP and RAPID arrays, Argo, satellite-derived), model-data synthesis (ASTE) and coupled models; (O2) Elucidate mechanisms driving changes in heat and FW budgets and creating rapid climate change thresholds; (O3) Assess impacts of ocean heat and FW changes on large-scale climate, including the risk of rapid change. A novel aspect of this approach pairs assessment of watermass transformation budgets with potential energy diagnostics and adjoint sensitivity mappings. These complementary perspectives are jointly accessible only within the state estimation framework and will shed new insights into the mechanisms via which remote forcings can reshape NA watermass distribution and destabilize convection. Additionally, the work will reveal potential predictability within the NA. 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.