Schematic diagram of the positive feedback between the AMO and FSSIE (IMAGE)
Caption
During the AMO+, the meridional gradient of the surface temperatures decreases, triggering more atmospheric blockings over Greenland (red rings with clockwise arrows). This high-pressure system weakens south-to-north meridional winds, reducing the FSSIE (dashed dark gray arrow). Consequently, this maintains the high salinity of the Labrador Sea and the strength of the AMOC (red shaded area), thus extending the AMO+ (double thick solid red arrows). Conversely, during the negative phase of the AMO (AMO–), the meridional gradient of surface temperatures increases. In the absence of atmospheric blocking, the low-pressure system (blue rings with anticlockwise arrows) facilitates greater FSSIE into the Labrador Sea (solid dark gray arrow), maintaining its low salinity and the weakened state of the AMOC (blue shaded area), thereby prolonging the AMO– (double thick solid blue arrows). Background of the image depicts the phase spatial pattern of the AMO. Dark gray area covering the Arctic represents the Arctic sea ice extent. Black arrows on the sea ice indicate the direction of sea ice movement. Curved arrows represent the influence of the ocean on the atmosphere.
Credit
Figure from Modeling the Atlantic Multidecadal Oscillation: The High-Resolution Ocean Brings the Timescale; the Atmosphere, the Amplitude, created by Xiaojie Hao.
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