Thermodynamical Drivers of Regional Warming in the Northeastern United States
SMAST East 101-103
: 836 S. Rodney French Boulevard, New Bedford MA 02744
Callie Rumbut
c.rumbut@umassd.edu
https://umassd.zoom.us/j/98165845430
Department of Fisheries Oceanography
MS Thesis Defense
"Thermodynamical Drivers of Regional Warming in the Northeastern United States"
By: Adriano Giangiardi
Advisor
Dr. Changsheng Chen (UMass Dartmouth)
Committee Members
Dr. Geoffrey Cowles (UMass Dartmouth), Dr. Siqi Li (UMass Dartmouth), and Dr. Lu Wang (UMass Dartmouth)
Monday August 10, 2026
2:00 PM
SMAST East 101-103
836 S. Rodney French Blvd, New Bedford
and via Zoom
Abstract:
The Gulf of Maine (GoM) is among the fastest-warming regions in the global ocean, with an observed basin-wide warming rate of approximately 0.05°C per year, substantially exceeding the global upper-ocean average. Although this accelerated warming has been well documented, the relative contributions of local atmospheric forcing and remote ocean heat transport have not been quantitatively determined. This thesis addresses this knowledge using the Northeast Coastal Ocean Forecast System (NECOFS) hindcast dataset. Atmospheric and oceanic fields from the NECOFS hindcast were used to construct a volume-integrated heat budget model for the GoM, enabling the relative contributions of surface air-sea heat fluxes and lateral heat transport to be quantified. The hindcast was first evaluated against observations of near-surface atmospheric variables, ocean currents, seawater temperature, and sea surface elevation, demonstrating good agreement across all evaluated variables. The heat budget was decomposed into local thermodynamic forcing (air-sea heat flux) and remote advective transport (lateral heat transport through the GoM boundaries). Comparisons between two representative periods (1995-2001 and 2017-2023) show that changes in heat transport account for approximately 93% of the increase in the basin heat budget, whereas enhanced local atmospheric heating contributes only about 7%. Further decomposition of the advective term reveals a substantial reorganization of the primary heat transport pathways. The dominant inflow shifted from the Scotian Shelf during 1995-2001 to the southwestern side of the Northeast Channel during 2017-2023, while the contribution from the Northeast Channel itself declined markedly. At the same time, reduced outflow through the Middle Atlantic Bight likely increased the residence time of warm water within the basin, further enhancing regional warming. River heat input remained negligible throughout both periods.
These results demonstrate that the recent acceleration of warming in the GoM is controlled primarily by changes in regional ocean circulation rather than by increased local atmospheric heating. The study provides a quantitative framework for distinguishing the relative roles of atmospheric forcing and oceanic heat transport in regional climate change and offers new insight into the physical mechanisms responsible for long-term warming in the northeastern U.S. shelf ecosystem.
Join Meeting
https://umassd.zoom.us/j/98165845430
Note: Meeting ID and passcode required, email contact to obtain.
For additional information, please contact Callie Rumbut at c.rumbut@umassd.edu