RT Journal Article SR Electronic T1 On the crucial role of atmospheric rivers in the two major Weddell Polynya events in 1973 and 2017 in Antarctica JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eabc2695 DO 10.1126/sciadv.abc2695 VO 6 IS 46 A1 Francis, Diana A1 Mattingly, Kyle S. A1 Temimi, Marouane A1 Massom, Rob A1 Heil, Petra YR 2020 UL http://advances.sciencemag.org/content/6/46/eabc2695.abstract AB This study reports the occurrence of intense atmospheric rivers (ARs) during the two large Weddell Polynya events in November 1973 and September 2017 and investigates their role in the opening events via their enhancement of sea ice melt. Few days before the polynya openings, persistent ARs maintained a sustained positive total energy flux at the surface, resulting in sea ice thinning and a decline in sea ice concentration in the Maud Rise region. The ARs were associated with anomalously high amounts of total precipitable water and cloud liquid water content exceeding 3 SDs above the climatological mean. The above-normal integrated water vapor transport (IVT above the 99th climatological percentile), as well as opaque cloud bands, warmed the surface (+10°C in skin and air temperature) via substantial increases (+250 W m−2) in downward longwave radiation and advection of warm air masses, resulting in sea ice melt and inhibited nighttime refreezing.