Figure 2. Sea-surface topography from ship drift: annual mean. The con- 

 tinuous contours show topography of the sea surface in cm based 

 on heights calculated from ship drift; the numerical values are 

 relative to an annual mean of 200 cm at Bermuda. The dashed con- 

 tours are an estimate of the part of the computed ship-drift 

 topography caused by the wind alone. The contour interval is 

 10 cm; the scale is 1:20x10^ at 30° on Mercator projection. 



24-6 



