Free-drifting ice moves ~2 % of wind speed at ~30° to the right of wind (Nansen rule) in northern hemisphere, plus any surface-current contribution.
Formula
$$ V_\text{ice} = 0.02 V_\text{wind} \oplus V_\text{current}, \quad \theta_\text{ice} = \theta_\text{wind towards} + 30^\circ $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $V_\text{wind}$ | Surface wind speed | kn | anemometer |
| $V_\text{current}$ | Surface current | kn | ADCP / model |
Sources
- Nansen (1902) - Oceanography of North Polar Basin.
- IMO Polar Code.