Observations of vertical temperature microstructure at ocean station P during the mixed layer experiment (Mile) indicate that the shape of the high-frequency temperature gradient spectrum depends on the relative strenghts of turbulence and strafification. For low Cox number ⟨(dT/dz)2⟩/⟨dT/dz⟩2 the linear range of the Batchelor spectrum is not well approximated by observed spectra, while for high Cox number a remarkably close correspondence to the Batchelor spectrum is found. Dissipation rates calculated by the temperature gradient spectrum cutoff wave number method show a dramatic contrast in turbulence between low and high wind speed periods separately by only 3 hours, showing that the response of the mixed layer and transition zone to wind forcing is rapid. Some indication is found that the thermocline may also respond rapidly to surface forcing.