Session: 07-01-01 Arctic Environments and Frontier Regions

Submission Number: 179801

Long-Term Relationship Between Marine Heatwaves and Sea-Ice Variability in the Arctic Ocean 

The Arctic Ocean is undergoing unprecedented warming, with surface temperatures increasing almost four times faster than the global average. In recent decades, this rapid warming has given rise to a newly recognised phenomenon; Arctic marine heatwaves (MHWs), which are prolonged periods of abnormally high sea-surface temperature (SST) that persist for days to months above the 95th percentile of long-term climatology. Although MHWs have been extensively studied in lower-latitude oceans, their emergence in the Arctic has only been systematically detected since 2007, coinciding with record sea-ice retreat and enhanced ocean–atmosphere coupling. Unlike at lower latitudes, MHWs in the Arctic can occur due to sea-ice retreats and consequently, a darkened ocean surface, raising questions about the direction and mechanisms of interaction between MHWs and sea-ice loss.

This study investigates the relationship between Arctic MHWs and sea-ice variability using the ORAS5 global ocean reanalysis dataset (1958–2024, 0.25° resolution). The analysis examines the coupled evolution of SST, sea-ice concentration (SIC), and ice thickness to determine where and when ocean heat anomalies emerge relative to ice retreat. Results identify regions of strong ocean–ice interaction, where reduced SIC coincides with intensified MHW events, particularly along Atlantic and Pacific inflow pathways. The findings discuss both surface warming following ice loss and heat transport from lower latitudes and their contribution to the amplification of Arctic MHWs, with their relative importance varying regionally. By distinguishing between cause and consequence in the MHW–ice system, this work improves understanding of the feedback mechanisms driving Arctic amplification, regionally, and provides a framework for assessing future navigational and ecological risks in a warming polar environment.

Presenting Author: Bahareh Kamranzad University of Strathclyde

Presenting Author Biography: Dr Bahareh Kamranzad leads the Coastal Engineering & Ocean Climate research group and the Strathclyde Centre for Doctoral Training (SCDT) in AI-Based Ocean Forecasts for Marine Operations at the University of Strathclyde. Her research focuses on climate-driven ocean dynamics, marine heatwaves, and sea-ice interactions, particularly their implications for Arctic navigation, offshore operations, and coastal resilience. Dr Kamranzad is the Principal Investigator of the Lloyd’s Register Foundation × UArctic Fellowship project “Impact of Marine Heatwaves on Sea Ice for Arctic Navigational Safety” and the Royal Society project “Arctic Wave Climate Response to Global Warming.” Her broader research portfolio combines reanalysis and satellite observations with numerical and AI-based models to assess ocean–atmosphere coupling, extreme events, and the sustainability of ocean renewable energy systems. She also serves as Deputy Editor for Ocean Engineering and on the Advisory Editorial Board for Coastal Engineering, with over 50 peer-reviewed publications and international recognition among the world’s top 2% of scientists.

Authors:

Bahareh Kamranzad University of Strathclyde
Ed Blockley Met Office Hadley Centre