Ocean circulation
Gulf Stream jumps as an AMOC-collapse warning
Open access · cc by · source: Europe PMC
In a 0.1° ocean hosing run, the Gulf Stream leaps north near 71.5°W years before AMOC collapses, a pattern also hinted at in altimetry.
Study at a glance
- Design
- Computational / modelling — 0.1° CESM-POP freshwater-hosing simulation of Gulf Stream path and AMOC collapse
- N
- Single high-resolution hosing experiment compared with RAPID/AVISO observations
- Population
- Simulated North Atlantic Gulf Stream / AMOC system under freshwater forcing
- Outcome
- Abrupt northward Gulf Stream jump as precursor to AMOC collapse
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
Initial AMOC is 19.9 Sv versus 17 Sv observed. After slow Deep Western Boundary Current weakening, the Stream jumps ~2° north at 71.5°W in model years 392–394, before AMOC collapses near year 420 to a 5.1 Sv remnant. Local SST jumps ~4°C in two years.
Methodology
Authors analyzed a high-resolution CESM-POP freshwater-hosing simulation, tracked the Gulf Stream with dynamic sea level and the 15°C north wall, and compared transports with RAPID, the Florida Current, GLORYS12, and AVISO.
Limitations
This is a stand-alone ocean hosing experiment, not a coupled CO2 scenario; Florida Current is 14% weak and DWBC 36% strong versus reanalysis, so lead times may differ in nature.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
In a 0.1° ocean hosing run, the Gulf Stream leaps north near 71.5°W years before AMOC collapses, a pattern also hinted at in altimetry.
Evidence for the claim as stated.
In a 0.1° CESM-POP freshwater-hosing simulation, AMOC starts at 19.9 Sv versus 17 Sv observed. After slow Deep Western Boundary Current weakening, the Gulf Stream jumps ~2° north at 71.5°W in model years 392–394 — tracked with dynamic sea level and the 15°C north wall — before AMOC collapses near year 420 to a 5.1 Sv remnant and local SST jumps ~4°C in two years. Transports are compared with RAPID, the Florida Current (model 14% weak), GLORYS12 and AVISO; the altimetry record is a path check, not the hosing experiment.
Evidence for the claim as stated.
Only two papers actually confront an altimeter product. The Gulf Stream jump is a hosing-model event with an AVISO northward-shift hint near separation; lead times may differ because the Florida Current is 14% weak and the DWBC 36% strong versus reanalysis. The dam paper is a mass-fingerprint budget term with no altimeter. Combining ‘AVISO shows the Stream jumped’ with ‘dams lowered GMSL 16.6 mm’ as two altimetry results is a category error.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Only two papers actually confront an altimeter product. The Gulf Stream jump is a hosing-model event with an AVISO northward-shift hint near separation; lead times may differ because the Florida Current is 14% weak and the DWBC 36% strong versus reanalysis. The dam paper is a mass-fingerprint budget term with no altimeter. Combining ‘AVISO shows the Stream jumped’ with ‘dams lowered GMSL 16.6 mm’ as two altimetry results is a category error.
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