Possible implications of terrestrial river discharge with Arctic coastal ice

Abstract:

@font-face { "ＭＳ 明朝"; }@font-face { "Cambria Math"; }@font-face { "@ＭＳ 明朝"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0mm 0mm 0.0001pt; font-size: 12pt; ""; }.MsoChpDefault { ; }div.WordSection1 { page: WordSection1; } One of the recent characteristic Arctic changes is the increase in river discharge flowing to the Arctic Ocean. The discharge simultaneously transports heat energy to the ocean. Under Arctic warming, the increased river discharge likely results in more heat flux to the Arctic Ocean. Interestingly, river discharge shows the peak in the spring season when Arctic sea ice begins to melt. At that time, the discharging heat flux may further contribute to sea ice retreat. A land surface model (CHANGE), coupled a river routing discharge model that combines river ice and water temperature models, simulated positive trends of pan-Arctic river discharge and water temperature, consequently enhanced heat flux to the Arctic Ocean. The increases were significant in Eurasian rivers and especially in the spring season. The model estimated cumulative heat flux to July was compared with the loss rate of sea ice concentration in Arctic coastal areas, revealing significantly higher correlation at Laptev and East Siberian seas where sea depth is shallower and the sea slope is not steep. Heat flux provided by river discharge had an ability that can melt approximately 10% or more of sea ice extent in Laptev and East Siberian seas, under the assumption that ice thickness is 1 m. This analysis provides an insight about influence of the terrestrial freshwater on the declining Arctic coastal sea ice.