Turbulence dynamics and micrometeorological characteristics of the atmospheric boundary layer are key to understanding, modeling, and forecasting the air pollution of urban areas. To precisely and directly measure turbulence and micrometeorological parameters, Remtech Fluxmeter, a new type of observation instrument, was used in this experiment. A detailed analysis of the collected data shows that most of micrometeorological elements possess remarkable daily cycles, quasi-four days waves and intra-seasonal fluctuations. Weather systems such as tropical cyclones and atmospheric fronts exert many-sided influences on the variations of the elements. Also, this study partially explained a puzzle about the variance of wind direction angle on stable conditions. In the second half of the work, t...[ Read more ]

Turbulence dynamics and micrometeorological characteristics of the atmospheric boundary layer are key to understanding, modeling, and forecasting the air pollution of urban areas. To precisely and directly measure turbulence and micrometeorological parameters, Remtech Fluxmeter, a new type of observation instrument, was used in this experiment. A detailed analysis of the collected data shows that most of micrometeorological elements possess remarkable daily cycles, quasi-four days waves and intra-seasonal fluctuations. Weather systems such as tropical cyclones and atmospheric fronts exert many-sided influences on the variations of the elements. Also, this study partially explained a puzzle about the variance of wind direction angle on stable conditions. In the second half of the work, the properties of nonhomogeneous turbulence and the similarity relationships among turbulence parameters under different stability conditions were revealed and a sensitive range of turbulence kinetic energy to heat flux and wind speed was found. Consequently the range proved to be significant in understanding certain critical phenomena. In the study of neutral cases, a practical testing method was proposed to help examine wind profiles for logarithmic rule without knowing roughness length in advance. A survey of momentum flux signs and a test for log wind profiles demonstrated that nonhomogeneous underlying surfaces have serious effects on the direction of momentum transportation and may destroy the structure of natural wind field. Finally, a comparison with other scholars' work suggests that the results obtained in the experiment not only broadly agree with other authors' conclusions but also successfully reveal some major particularities in uneven terrain conditions. The work thus offers a valuable data set to the boundary layer study of Hong Kong.