The Effect of Indian Ocean Surface Freshwater Flux Biases On the Multi-Stable Regime of the AMOC

• Published in: Tellus A: Dynamic Meteorology and Oceanography
• Main Authors: Henk A. Dijkstra, René M. van Westen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Stockholm University Press 2024
• Subjects: atlantic ocean circulation; freshwater flux biases; bifurcation analysis; Oceanography; GC1-1581; Meteorology. Climatology; QC851-999; North Atlantic
• Online Access: https://doi.org/10.16993/tellusa.3246; https://doaj.org/article/6e619c03f9714f92abda745cd08953d9

It is known that global climate models (GCMs) have substantial biases in the surface freshwater flux. Using numerical bifurcation analyses on a global ocean model, we study here the effect of freshwater flux biases over the Indian Ocean on the multiple equilibrium regime of the Atlantic Meridional Overturning Circulation (AMOC). We find that a (positive) freshwater flux bias over the Indian Ocean shifts the multiple equilibrium regime to larger values of North Atlantic freshwater input but hardly affects the associated hysteresis width. The magnitude of this shift depends on the way the anomalous North Atlantic freshwater flux is compensated. The changes in bifurcation diagrams can be explained from the overall freshwater balance over the Atlantic basin.