Most floats travel some 10–40 km between successive data
transmissions, but there is also a considerable range of larger distances. Very large distances are produced by data transmission
failures causing gaps in the time series. Assuming
that about half the float movement is caused by drift at the
surface and the other half by drift at the parking depth, the
standard deviations of Fig. 2 indicate the degree of variability
on space scales varying from 5 km to about 100 km and
more.