Mechanisms and predictability of subsurface marine heatwaves along the continental shelf of eastern US
PI: Laifang Li (Meteorology and Atmospheric Science, ICDS, and EESI)
The project will partially cover salaries for postdoc and/or research faculty with the remainder of the funding from an NSF grant.
Project Description
The continental shelf of the eastern US is a hot spot for subsurface marine heatwaves. These heatwaves, compared to their surface counterparts, more directly impact marine ecosystems and fisheries. For example, in the January of 2017, Rhode Island commercial f ishers reported an unusual bycatch of warm water species including Gulf Stream flounders. Later on, the water mass anomalies were observed by instruments onboarding commercial f ishing vessels (Gawarkiewicz et al. 2019). Case study of the 2017 subsurface marine heatwave showed that cyclonic eddies in close to the shelf preconditioned the warmth at depth which was subsequently intensified onshore by strong and persistent upwelling winds (Chen et al. 2022). The findings from the 2017 case motivate the PI to assess the predictability of subsurface marine heat waves, in particular, whether or not large-scale atmospheric patterns are connected to the initialization of subsurface marine heatwaves.
In this project, the PI propose to investigate manifestation of the subsurface marine heatwaves in the past 30 years, further elucidate the initialization mechanisms of subsurface heatwaves, and assess their predictability using the high-resolution (~1 km) regional ocean modeling system (ROMS). Firstly, the subsurface marine heatwaves along the continental shelf of the Eastern US will be identified by applying Self Organizing Map (SOM) to the slope-bottom temperature from the GLORYS ocean reanalysis product. Based on the SOM identification, the atmospheric circulation parameters (e.g., pressure, wind, heat flux) and ocean state and dynamic variables (e.g., temperature, salinity, currents, sea surface height) prior to the subsurface marine heatwave events will be analyzed to identify the largescale precursors that leads to subsurface heatwaves. Based on the results, ocean temperature budget analysis will then be performed to diagnose the mechanisms through which the subsurface marine heatwaves are initiated and intensified under the identified atmosphere and ocean conditions. This analysis will involve collaboration with scientists at the Woods Hole Oceanographic Institution. Finally, the predictability of subsurface marine heatwaves will be assessed by performing idealized simulations with the ROMS. As an initial plan, four primary sets of experiment will be conducted: 1) control experiments in which the atmosphere and ocean parameters from the SOM analysis will be supplied to the ROMS; 2) wind forcing only experiment; and 3) open ocean warming only experiment. From these experiments, the base line predictive skills of subsurface marine heatwaves from precedent atmospheric and oceanic conditions will be assessed. More importantly, the key factors that lead to the initiation of subsurface marine heatwaves will be identified to inform the monitoring and early warning of anomalous subsurface warming events for fisheries.
Specific Areas of Computational and/or Data Science Expertise the current team is particularly interested in recruiting are: 1) capability to handle ocean reanalysis products with irregular grid spacing, such as the ECCO data and the GLORYS; 2) experience conducting regional or global climate model simulations, especially eddy-resolving simulations; 3) knowledge of spatial statistics with Earth Science applications.
Requirements and Expectations: The project looks for a highly motivated junior researcher with background training in Ocean and Climate Dynamics. The researcher is expected to work in a collaborative environment, as the project will involve interactions with scientists at Woods Hole Oceanographic Institution. Research progress should be reported to the PI in a timely and regular manner through written report or oral presentation during weekly group meetings.
Specific Objectives: The data from the project will be used to revise an NSF proposal, which was declined by the Physical Oceanography program even with Excellent and Very Good ratings. The primary comments were on the usage of the SOM, which is not yet a common practice by physical oceanographers, and the program manager suggest the PI to show proof of concept of the methodology in the revision. Similarly, the junior researchers involved in this project can utilize the project outcome as preliminary data for their fellowship applications (e.g., the NASA FINESST or NSF Postdoc fellowship). For both cases, at least one peer-reviewed journal article will be expected from the project study.
Medium to Long-Term Goals: 1) secure external funding (e.g., NSF PO and NOAA CPO) for marine heat wave study at PSU; 2) Improve the mechanistic understanding and forecast skill of subsurface marine heat waves along the continental shelf of the Eastern US; 3) Outreach and interaction with fishing communities by providing updated oceanic conditions for a given region along the eastern coast.
Connection to ICDS’s mission: The project will support an interdisciplinary research that combines machine learning and high-resolution regional modeling approaches for improved prediction of high-impact ocean heat extremes. The project outcome will enhance our understanding of Earth system predictability and benefit the fisheries along the US eastern coast which support local economy.
Recent and planned engagement with ICDS: The PI is an ICDS co-hire and has actively participated in ICDS sponsored activities, like judging the poster presentations at the ICDS symposium. Through this ICDS support, the PI and the selected junior researcher will plan to: 1) present the research findings at the upcoming ICDS symposium; and 2) host a future NOAA Climate Diagnostic and Prediction Workshop at Penn State, through the joint sponsorship among ICDS and the Department of Meteorology and Atmospheric Science. The PI has successfully hosted the 44th workshop at Duke University when she was a postdoctoral researcher.