Figure sal1:1 The potential density in the perturbed initial conditions. On the left, at 666m depth. On the right along the Greenwich Meridian (0E/W). In the unperturbed initial conditions the yellow, orange, red and brown colours do not appear.
Figure sal1:2 Potential density along the Greenwich Meridian overlayed with the zonal velocity along the same meridian (units cm/s) during the first and second winter (DJF average).
Figure sal1:3 SST difference between the mean of the perturbed ensemble and the mean of the control ensemble averaged over the first and second winter (DJF). Units are degrees Celsius.
Figure sal1:4 Vertical profiles of salinity (left) and temperature (right). The profiles represent an average over the GIN Seas, defined as 65N to 80N and 30W to 10E. The black profile is an average of the four first winters (DJF) in the control ensemble mean. The coloured profiles are the first four winters (DJF) in the perturbed ensemble mean. Red is followed by green, dark blue then light blue.
Figure sal1:5 An estimate of the temperature (left) and salinity (right) of the Denmark Strait overflow into the North Atlantic. Each value is an average over all points in the seasonal mean which have a density greater than 28.05 and is within the volume encompassed by 61.9N to 65.6N, 40W to 26W and 0 to 3039m depth. The value 28.05 was chosen from studying the control run to find a value which can identify overflow water.
Figure sal1:6 Normalised density anomaly integrated from the surface to 3000m overlayed with total velocity from the perturbed ensemble integrated to the same depth for the first winter (DJF) and the following autumn (SON). The normalised density anomaly is calculated by dividing the difference in density (perturbed - control) by the square root of the average variance within the two ensembles.
Figure sal1:7 Perturbed ensemble mean salinity (left) and temperature (right) sections in the Labrador Sea averaged over 56.9N to 59.4N. Black is for the first winter (DJF) and red for the following winter.
Figure sal1:8 Meridional overturning index for the control ensemble mean (black) and the perturbed ensemble mean (red). The index is calculated as the average value between 27.5N and 32.5N of the zonally averaged meridional streamfunction at 1000m depth.
Figure sal1:9 Five year average (third to eighth year in run) depth cross section of potential density at 32N in the control ensemble mean (black) and the perturbed ensemble mean (red).
Figure sal1:10 Normalised temperature (right column) and salinity (left column) anomalies at 2000m (top row) and 3300m (bottom row) for the tenth and last winter of the model runs. The normalised anomalies are calculated by taking the difference beween the perturbed ensemble mean and the control ensemble mean and dividing it by the square root of the average variance within the model ensembles.