Solar heating

After passing through the Bering Strait, the Pacific Summer Water is not transported directly to the Arctic Ocean basin (a sea area with a depth of several thousand meters), but is heated by sunlight in the Chukchi Sea, which is a shelf area. This heating, called solar heating, is large, not only in the south where the solar radiation is strong, but also near the coast of mainland Alaska, which is the main northward route of the Pacific Summer Water. This is likely because the albedo became small as a result of the decline in sea ice in the Chukchi Sea, making it easier for heat to enter the ocean.

Albedo is the ratio of reflected light to incident light. When the ocean is covered with ice, much of the sunlight is reflected, and the albedo is close to 1. When the ocean is not covered with ice, most of the sunlight is absorbed by the ocean, making the value of albedo 0.1 or lower.

Excerpted from Tsukada, Ueno et al., Polar Science (2018).