Measurements of ε in the nocturnal stable boundary layer show values as low as about 10-7 m2 s-3. When compared to tower measurements of turbulence by means of σ w 2, data reveal a good correlation. Our results show that a) even in the most stable boundary layer, a residual turbulence is always present, and b) ε observations are useful even at low turbulence levels. Measuring ε with the TLS system also provides identification of the boundary layer type, its height, and dynamical characteristics. Furthermore, depending on environmental conditions, TLS measurements of turbulence are much less sensitive to the averaging timescale than standard tower measurements.