Fig. 4: Time series of ocean-atmospheric conditions during polar cyclones.

Daily anomalies in (a) mean sea level pressure (MSLP), wind stress curl, (b) surface air temperature (SAT), ocean mixed layer temperature (MLT), sea surface temperature derived from blending of microwave and infrared observations (MW IR SST), (c) net heat flux (NHF), downward long-wave radiation (DLR), integrated water vapor flux (IWVF), (d) significant wave height (SWH, blue line) of combined wind waves (WW) and swells (S), individual contributions from swells (yellow line), WW (dotted purple line) and total precipitation (red line) during 01 February–31 May 2019, spatially-averaged over the Weddell Sea within the green rectangle shown in Fig. 2a. The daily minimum and maximum anomalies of ocean‒atmospheric variables are shown in Supplementary Fig. 4. Vertical color-shaded bars represent the occurrence period of cyclones (C1, C3, C8, C11) corresponding to the largest rate of sea ice changes in the Weddell Sea (See plus marks in Fig. 2c). The anomalies are computed relative to the climatology of 1979–2008.