Study Of Turbulence Characteristics Of Surface Layer Over Tazhong Of Taklimakan Desert

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 provide service of Micrometeorology for exploitation of natural gas and oil in Tazhong area, simultaneously also makes the desert hinterland surface layer fundamental research deeply. The eddy covariance (EC) technique can measure turbulent exchanges between surface and atmosphere most available, most directly, and most exactly.Using these data from the OPEC fast response detection system at 32m height in the desert center atmospheric environment inspection station—tazhong and 3m height in the west correct station, researched the atmospheric boundary lower layer turbulence dynamical characteristics, analyzed the correlative turbulence characteristics in the sand storm weather process, drawed the following main conclusions:(1) The peak value of atmospheric stability between -0.2 and 0.2 whether day time or night time, it is near neutral. The mean horizontal turbulence intensit is 0.35, the mean vertical turbulence intensit is 0.04, and I_u>I_v>I_w. The turbulence intesity of daytime is higher than the night time. The turbulence intensit exponential attenuate.with the augment of mean wind speed.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.(2) Under the different stable conditions, the relations dimensionless component of velocity variance with the stability conform to the similarity theory power rules in four seasons.And the similarity functions is closer to Gobi desert, obey the law of 1/3 fraction power.The dimensionless component of temperature and vapor is abroad compare to other areas. It is similarly in different seasons.(3)The turbulent kinetic energy, the rubbing speed and the characteristic temperature display obvious diurnal variation characteristic.The pattern of characteristic temperature took on inverse"U"shapes according to their diurnal changes and it is positive during daytime while it is minus during night. The pattern of rubbing speed is symmetric with 13:00. Under the unstable condition, the rubbing speed increase slowly with the stability; while under the stable condition, the rubbing speed decrease rapidly with the stability. The data of characteristic temperature distribute uniformly in the first and the third quadrants, when it is closer to (0, 0) it will be more centralize.(4) The heat transport mainly is the sensible heat flux in Tazhong area, and the latent heat flux is as small as 1/10 of the sensible heat flux. The sensible heat flux display obvious diurnal variation characteristic, .and it took on inverse"U"shapes according to their diurnal changes. The diurnal changes range of the sensible heat flux are different, summer> autumn> spring> winter. The sensible heat and the latent heat are more fluctuate and less than clear day in a dust and sand weather.(5) The momentum flux of 32m height display obvious diurnal variation characteristic, it's present one peak shape obviously and similar with the diurnal variation of temperature . The momentum flux is increasing with the raise of the sun, and it reached the max at 13:30, then the momentum flux minished, untill reached it's minimum at 24:00 during nighttime. The range of change is larger during daytime but it's quite small during nighttime. The momentum fluxes are obviously different in dust and sand weather from clear day.(6) Three directions of the turbulent kinetic energy represent the u direction is the largest, v and w directions are nearly, and both of v and w are nearly the same during the midday. By using the eddy covariance material of the 32m height,we caculate the varied range of CD is 10^-4～10^-2, and CD is unlikely in different stability conditons. CD is decreased with the stability under stability and untability conditons, but it decrease more quickly under stability condition.