Velocity statistics in the atmospheric surface layer over a desert.

摘要

During "Dugway 2005," all atmospheric surface layer experiment performed over a Utah desert, sonic anemometers at heights up to 26 in above ground collected 20 Hz time series of the components (u, v, w) of wind velocity, and temperature (T). In this thesis Dugway statistics (1-hr intervals) are analyzed according to the tenets of Monin-Obukhov (MO) Similarity Theory, i.e. statistics have been normalized using as "natural scales" the friction velocity u*, the Obukhov length L, and a related temperature scale T* . Streamwise velocity spectra are computed, and the turbulent kinetic energy (TKE) dissipation rate (epsilon) and boundary layer depth (delta) deduced from them; epsilon is well approximated by the rate of production of TKE. Runs with extremely unstable stratification permit a cursory evaluation of McNaughton's alternative scaling theory, whose application requires as input the dissipation rate (epsilon0) of the "outer layer." For those cases Dugway statistics do order with z/zs, though not as tidily as they do under MO scaling.