Fig. 4

Meridional heat transport from observations and numerical model results. a Estimates of meridional heat transport for the upper 1,000 m across the glider section at 58°N between 24.5 and 21°W using glider observations. The estimated values, representing monthly averaged ocean state, are shown together with error bars illustrating the uncertainties due to depth-averaged velocity from the glider data. The results are separated into eddy (blue) and frontal (red) patterns. The transitional periods between eddy and front are shown in black. The magenta lines show the heat transport induced by velocity change in glider observations (a) and numerical model (b). Black line in (b) denotes the simulated monthly time series of meridional heat transport for the upper 1,000 m along the glider section. For comparison, the simulated mean heat transport across the glider section is 0.24 PW in the upper 1,000 m. Blue and red dots mark the eddy and front scenarios in the model. The months between those dots are transitional periods. c The interanual anomalies for the heat transport induced by the large-scale (black solid) and mesoscale processes (black dashed) in the Iceland Basin, respectively, are displayed. The interanual heat transport anomalies across the Iceland Basin (29–19°W, including both large-scale and mesoscale processes) is shown in blue. Unit: PW