Observational Study Of Turbulence Characteristics Of Surface Layer Over Hinterland Of Taklimakan Desert

The atmospheric boundary layer is the place of main proliferation and consumed for the surface material and the energy. The research in desert boundary layer has the extremely close relationship to the simulation of desert region Land -Gas interaction. The Taklimakan desert is the world second large flowing desert, simultaneously is also Chinese desert typical representative. The research to boundary layer over hinterland of Taklimakan flowing desert might have active function for desert peripheral city development, simultaneously also makes the desert hinterland surface layer fundamental research deeply. Using these data from the 80m gradient survey and OPEC fast response detection system at 10m height in the desert center atmospheric environment inspection station-tazhong, this article has amply researched the atmospheric boundary lower layer turbulence dynamical characteristics, analyzed the correlative turbulence characteristics in the sand storm weather process, draws the following main conclusions:(1) Under the unstable and stable condition, the relations desert hinterland surface layer dimensionless component of velocity variance with the stability conform to the similarity theory power rules in spring, summer and winter but the best power has the difference respectively, not the only "1/3 power". Under the unstable condition, the dimensionless temperature variance conforms to the "-1/3 power" rules in summer, other seasons the dispersions are large, the rules are not obvious. Under near neutral condition, three direction dimensionless component of velocity variance are close constants, the overall performance is: The u direction is biggest, the v direction next best, the w direction is smallest. The turbulence intensity also has the similar rule.(2) The desert hinterland turbulent kinetic energy, the rubbing speed and the characteristic temperature display obvious diurnal variation characteristic. The rubbing speed reduces along with the stable or unstable degree increases, but the maximum value appears at z/L = -0.2 . The Euler time autocorrelation coefficient displays the over damp and gradually weakens two types.(3) The desert hinterland turbulent kinetic energy is related to the seasonal variation. The TKE is slightly larger in summer than spring, the smallest in winter. Horizontal direction's turbulent kinetic energy occupies the dominant position, the influence of plumb direction is small in the turbulent total kinetic energy. Under the unstable condition, the thermal energy provides obvious strongly than the mechanical. Under stable condition, both of them effect is equally. The dimensionless perturbation kinetic energy increases along with increase of stable or the unstable degree, the dispersion degree is also increase.(4)The Euler time autocorrelation coefficient displays the fast decay, slow decay and gradual decay three types. During the different condition, Euler time autocorrelation coefficient in the sand storm decays strongly than fine day.(5) Under the unstable condition, the standard day vertical pulsation peculiarity is primarily at the 12-17s time scale, the smallest time scale appears at 1-1.5s in spring, while the sand storm main time scale is about 6-10s, the smallest is 0.3-0.5s. Under the stable condition, at the standard day the time scale is around 10-16s primarily, the most short time scale is at 0.7-1s, the sand storm vibrates at the 11 -20s time scale strongly, the smallest time scale is about 0.4-0.6s.