On the Turbulence Quantities in the Neutral Atmospheric Boundary Layer

[摘要] The turbulence quantities such as the RMS of vertical wind speed σw, the dissipation rate of kinetic energy to heat ε, and the vertical diffusion coefficient KM in the planetary boundary layer under near-neutral stability are considered. In this layer, observations have shown that σw is proportional to the friction velocity u* and decreases approximately linearly with height. Based upon these observations, u* is approximated byu*=u*0ζwhere u* is the friction velocity at height z, suffix 0 denotes the value at the surface and ζ=1- z/h, h is the characteristic scale height relating to the thickness of the boundary layer.The turbulence quantities are related to u* by replacing u*0 in the relations given by the similarity theory attributed to Monin and Obukhov (1954), for the constant flux layer, these are as follows;σw=Cwu*0ζε=u*03ζ3/(kz)KM+CKwhere C with suffix w or KM is constant, k is _??_ constant.The above relations hold fairly well with the observations taken in lower region of the boundary layer below the height of 700 to 1000m approximately.

[学科分类] 大气科学