AbstractWave and aerodynamic properties of the sea surface at Lough Neagh, Northern Ireland, are described with mean wind speedu(at a height of 10 m) varying from 4 to 8 m s−1and fetchFvarying from 8 to 22 km.The sea surface at Lough Neagh is characterized by wind induced waves of dominant period 2 to 4 s and a wave spectrum depending uponuandF, with a steep low frequency face (at frequency nf), sharp peak (at no) and high frequency region with ‘energy’ proportional to frequency to a variable power β in the range —4 to —5. The ‘constant’ of proportionality αg2in the relation ϕ(n) = αg2n−βappropriate to the equilibrium range is variable between 6 and 12 (where unless stated to the contrary n in numerical expressions is in cycles s−1)‐ mean of 7·9 ‐with a mean β of —4·5, which compares to Phillips' overall mean value of αg2of 7·2 with a mean β close to —5.Our data, and those from other sources, suggest the following relations, valid over a range of the dimensionless fetchgF/u2from 102to 105,\documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma \eta {\rm /F = 2}{\rm .0 X }\mathop {{\rm 10}}\nolimits^{{\rm - 4}} {\rm (gF/}\mathop {\rm u}\nolimits^{\rm 2} {\rm)}^{{\rm - 0}{\rm .40}} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ n_o {\rm u/g = 2}{\rm .6(gF/}\mathop {\rm u}\nolimits^{\rm 2} {\rm )}^{{\rm - 0}{\rm .30}} $$\end{document}And\documentclass{article}\pagestyle{empty}\begin{document}$$ nf^{\rm 2} {\rm F/g = f(g/nfu) or F/}\lambda _{\rm f} = \,{\rm f(cf/u)}{\rm .} $$\end{document}The first two are found to imply σh= 1·4 n−2o.The third relation is interpreted through identification ofnfwith the transition frequency separating a linear from an exponential wave growth.Our data are consistent with the idea of Kitaigorodskii thatzo(u*) depends also upon the degree of wave development σ =gσh/u*2. At Lough Neagh σ* ∼ 10–40, implyingzois closely related tou* as is found to be the case using logarithmic wind profiles.There is evidence that\documentclass{article}\pagestyle{empty}\begin{document}$$ z_o \, \approx \,0.1\,\sigma \eta \,\exp (- \kappa C_o /u_*) $$\end{document}Suggested by earlier Russian work for similar values of σ*.There is no evidence that wave power impresses itself upon the turbulence spectra of the air for value