A special profiler with temperature and conductivity sensors allowed the study of the vertical structure of the near-surface layer (in the millimetre range) in the upper 10-m layer of the ocean under conditions of low wind speed. The measurements were in several regions of the Atlantic Ocean. In daytime thin homogeneous layers (sometimes several decimetres thick) and thermoclines below the layers have been observed. Complicated microstructure was often observed in the thermocline with vertical gradients of considerable values. Sometimes stepped structures, apparently caused by Kelvin-Helmholz instability, were observed. During the night the convective elements have been observed near the surface. Strong influence of rainfall on the vertical structure of the ocean near-surface layer has been observed.