Extended Data Fig. 3: Monthly average low–medium level cloud cover anomalies during May, June, July and August 2023.
From: Drivers of the extreme North Atlantic marine heatwave during 2023
a–d, Cloud cover anomalies are shaded and calculated as a fraction (values ranging from 0 to 1) relative to the 1981–2010 mean. Low–medium cloud cover corresponds to the total cloud cover from the surface up to a height of approximately 450 hPa. The +1 °C and −1 °C SST anomaly contours from Fig. 2 are overlaid in red and blue, respectively. To avoid any ambiguity, the regions of anomalous warming are indicated by the small red tick marks added around the +1 °C anomaly contour. Cloud cover anomalies are calculated from hourly ERA5 data.
