I. Some measurements of atmospheric turbulence

Abstract

The following notation is used throughout. The co-ordinate axes are a right-handed rectangular system x, y, h , in which 0 h is directed vertically upwards, and 0 x lies in any azimuth which happens to be convenient. Elements of distance to east and to north are denoted by de, dn , so that they are special cases of, dx, dy . The atmospheric density is ρ, the pressure is p , acceleration of gravity is g , latitude ϕ is reckoned negative in the southern hemisphere, and ω is the angular velocity of the earth. Velocities are denoted by v with a suffix to indicate the direction towards which they blow. Momenta per unit volume are denoted by m x , m Y , m H . The eddy-diffusivity is denoted by a capital K as in G. I. Taylor’s recent papers. Another, and in the author’s opinion a better, measure of turbulence is ξ discussed in a previous paper. The relation K to ξ is given by ∂/∂p(ξ ∂χ/∂p) ═ ∂χ/∂t ═ ∂ 2 x/∂h 2 ........(1) where χ is either potential temperature, or else mass of water or smoke per mass of atmosphere. If ρ and ξ were independent of height, then from (l) we should have ξ ═ g 2 ρ 3 K.............(2) It is suggested that ξ might be named “the turbulivity.” Its dimensions are: (mass) 2 x (length) -2 x (time) -5 .