This is because that frequency shift can also be found in the wind vortex over the arctic ocean , u - wind in beaufort sea , v - wind in east siberian sea and the pdo index 因此,除热力因素外,动力因素引起的海冰的平流与该变频现象也存在一定的联系。
百科解释
The Beaufort Sea () is a marginal sea of the Arctic Ocean, located north of the Northwest Territories, the Yukon, and Alaska, west of Canada's Arctic islands. The sea is named after hydrographer Sir Francis Beaufort.