Changes in Arctic sea ice drift speed over the last 130 years

Abstract. The Arctic transpolar sea ice drift speed shows a pronounced increase over past decades, one of many manifestations of Arctic climate change. However, little is known so far how the drift changed in earlier periods. Here I use data from historical drift expeditions, in particular from the Fram in 1893–96, the Sedov in 1937–40, the Tara in 2007–08, and the Polarstern during MOSAiC in 2019–20, as well as from the Soviet/Russian North Pole drift stations, to derive a 130-year record of Arctic transpolar drift speed. The transpolar drift speed already increased significantly during the early 20^th century warming, followed by a period of slowing drift in the 1950s–70s and a strong increase in recent decades, closely following the evolution of Arctic mean temperatures. The observed fractal scaling of the drifts can be explained quantitatively by a Brownian motion random walk process that includes temporal auto-correlation and a mean drift term due to currents and prevailing winds. Comparisons of the sea ice drift speeds with near surface wind observations reveal that the long-term changes in drift speed are not primarily caused by changes in wind speed.