Variability in Sea Ice Melt Onset in the Arctic Northeast Passage: Seesaw of the Laptev Sea and the East Siberian Sea

Abstract

AbstractIce/snow melt onset (MO) is critical timing for ice‐albedo positive feedback in the Arctic. For 1979–1998, the MO in the East Siberian Sea (ESS) occurred earlier than in the Laptev Sea (LS) for 12 of 20 years. However, for 1999–2018, the LS experienced significantly earlier MO than the ESS for 8 of 20 years. We referred to this phenomenon as the MO Seesaw (MOS) and quantified it by the MO difference between the LS and ESS. The MOS is more pronounced since 1999. For positive MOS, storm tracks in May are located south of the ESS and easterly wind prevails, resulting in higher surface air temperature and total‐column water vapor and, therefore, earlier MO in the ESS. For negative MOS, storm tracks are located southwest of the LS, and strong southerly/southwesterly winds bring warm air from coastal land toward the LS. When low pressure is centered over the Barents Sea in April, sea ice in the LS has driven away from the coasts, which increases the surface latent heat flux and humidifies the overlying atmosphere, and eventually leads to earlier MO in the LS. Both the local variables and the large‐scale atmospheric circulation indices were more related to the MOS for 1999–2018 than for 1979–1998.