The spatial variability of eddy fluxes in the constant flux layer

At the 1970 International Comparison of Turbulence Instruments held at Tsimlyansk, U.S.S.R., a large number of momentum and heat flux measurements were obtained simultaneously with two Fluxatrons. The data are analysed from the point of view of spatial variation of eddy fluxes, bearing in mind the limitations of the sensors, the variability of the eddy fluxes themselves, and the possibility of errors due to tilt. It is concluded that, at the Tsimlyansk site, the variation of heat and momentum fluxes both in the vertical (4 – 14 m) and the horizontal (1 – 150 m) is of the order 10 per cent or less. This result is in accord with traditional opinion, and provides a satisfactory experimental basis for the concept of a ‘constant flux layer’.