2.2. Current and slippage
The current vectors used in this study are taken at
0.5 m depth. This coincides with the draft of typical
SAR objects and roughly with the depth at which
current meters are mounted in leeway field experiments.
The slippage of an object is defined as its motion relative
to the ambient current at a certain depth comparable to
the draft of the object (set to 0.5 m in our case). In the
absence of wind, the object is assumed to move with the
local surface current, uw, i.e., no slippage. The object is
further assumed to adjust its motion instantaneously
when the current changes (infinite acceleration, discussed
above).