Observational Study on the Turbulent Structure of the Atmospheric Boundary Layer under Stable Conditions

[摘要] The turbulent structure under stable conditions in the atmospheric boundary layer (ABL) has been investigated by tower measurements, of the turbulent fluctuations and vertical mean profiles of wind velocity and air temperature. The results are summarized as follows:(1) For the parameter of thickness of the turbulent ABL under stable conditions, the height hq at which turbulent heat flux disappears is a more reasonable choice than the height hθ derived from the potential temperature profile, and hq has linear relation to the Monin-Obukhov stability length.(2) Unlike the constant flux layer near the ground, the absolute values of vertical heat flux (q) and momentum flux (u*) decrease with height in the stable ABL.According to these results, the ABL model proposed by Yokoyama et al. (1977, 1979) is applied to the turbulent ABL under stable conditions. We conclude that the vertical profiles of q and u* are approximated by the power function ζm andζn, respectively (where, ζ=1-z/hq, z: height, hq: thickness of the layer, m _??_3/2, n _??_1/2) and the same relations which described the turbulence quantities, temperature and wind velocity gradients in the constant flux layer are valid for whole stable ABL by replacing surface values of q and u* by their local values.

[学科分类] 大气科学