| 13 May 2026
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 20th 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.
Review of egusphere-2026-2561
Changes in Arctic sea ice drift speed over the last 130 years by Sinnhuber, B.-M.
Summary:
The manuscript analyzes observations from historical Arctic drift expeditions, including both ship-based expeditions and drifting stations established on sea ice, beginning with the Fram expedition. The author investigates changes in drift duration and velocity across the Arctic Basin and discusses these changes in relation to long-term and recent trends in Arctic climate and sea-ice cover. Analyzing the changes in drift velocities and wind factors through time, the author proposes air temperature-driven changes in ice thickness to be a major factor controlling the variations in average transpolar sea ice drifts speeds in the central Arctic Basin. The author also calculates the scaling exponent of drift velocities for historical drifts and demonstrates the similarity of the results with a random walk model with autocorrelation and a mean drift term. I prefer to refrain though from commenting on the implications of this part of the analysis, since I am not an expert in sea ice kinematics and dynamics at such level of detail.
The paper is well written in my opinion, and I got only one moderate to major comment. I believe the author can elaborate more on the issue he raised at the very end of the Discussion part, namely the drift of the wreckage of Jeannette to south-western Greenland. The wreck was found drifting with the ice, not stranded ashore. This provides quite reliable starting point for some basic analysis of the timing this could take for the wreckage to drift along the eastern shore of Greenland towards the recovery location. With these estimates at hand, one can have a better idea of how long it took for the wreckage to drift across the central Arctic, hence adding another valuable point in Figure 5. The author can use the data from https://iabp.apl.uw.edu to identify the buoys that travelled all the way to south-west Greenland with the E(W)GC and making drift duration estimates. Even if the values are to be very likely biased low due to the observed recent acceleration of the TPD, those will undoubtedly resolve if this could last “at least 400 days” as was postulated by Nansen back in the days.
Minor comments.
Line 120: …”but not considered in the present study”. Why these observations were discarded?
Line 145: “the absolute amounts of the drift speeds” – may be “values”?
Line 205: “…drift speeds as a function of the time intervals between the two positions”. How was this calculated? Random draws from the data set?
Figure 6: “…indicate the 2-sigma uncertainty derived from the observed drift speeds”. Is this sigma corrected for autocorrelation?
Figure 8: I recommend choosing different color scheme or/and use different symbols, otherwise hard to distinguish between different circles. Also, daily ice drifts are shown for mixed wind speeds for the three different experiments; I would suggest applying correcting factors to put them on the same wind speed scale, say 10m, even if it leads to some additional uncertainty.
Line 247: “…and concentration, leading to a faster drift…” Changing sea ice roughness/oceanic and atmospheric drags also considered as one of the factors (see e.g. Krumpen, T., et al. Smoother sea ice with fewer pressure ridges in a more dynamic Arctic. Nat. Clim. Chang. 15, 66–72 (2025). https://doi.org/10.1038/s41558-024-02199-5) though its significance in the overall picture is not yet fully understood.
Eq.(1) is it valid for free drift? Note that when making estimates below, the changes in the drag coefficients can also be considered.
Line 278: “…by scaling the random speeds by 1/sqrt(((1-r)/(1+r)))…” I assume this is to account for the increasing effect of autocorrelation at shorter time intervals; should the sqrt(n) factor be also included? Or it applies to daily velocities only?
Line 279:”…resulting then in an increased variance at long intervals (cyan lines in Figure 9).” The variance would increase for the ordinary Brownian motion too (see black lines in Figure 6), but positive autocorrelation would make the process to spread faster than a standard random walk by a factor of (1+r)/(1-r).
Line 279: ” …inclusion of a mean drift term results….” I believe adding another equation (e.g. into Appendix) for a modified Brownian motion could be a good idea.
Line 301 “…to the detection of the remnants” – may be “finding/recover of the wreckage of” can be a better formulation?
Line 314 ”…provide a 130-years time series of Arctic sea ice drift…” I believe this statement is far too ambitious given the scarcity of the data in the early part of the period considered. Please reformulate.