Atmospheric rivers and the onset of Arctic sea ice melt

The fast-changing Arctic climate is ultimately determined by a balance between heat imported from the south, predominantly in the atmosphere, and energy lost to space by radiation at the top of the Arctic atmosphere.

A disproportionately large fraction of the imported heat comes in spatially narrow and temporally discrete intrusions of warm and moist air sometimes referred to as “atmospheric rivers” (ARs).

ARs in general has a very large effect on the surface energy budget and we hypothesize that they are are responsible for triggering the onset of the sea-ice melt in spring, by altering the surface energy budget and hence surface characteristrics. ARs and the initiation of surface melt in the Arctic are both poorly understood.

Although sattelite observations are plentiful, there are almost no in-stu and no detailed spring observations at all.

We will therefore deploy the Swedish research icebreaker Oden in the Arctic during spring 2023 and use specialized ensemble weather forecasts to identify timing the location of ARs, and then navigate Oden into an optimal position from which we can observe the surface/atmosphere interaction, using in-situ and remote sensing instruments on board.

Observations taken in-between AR events will provide a spring time baseline.

Most observations from Oden will be performed from on board the ship, with the Arctic Climate Across Scales atmospheric observatory, while shorter ice-based observations deployed near the ship when it is stationary.