长江口湍流剖面的观测与分析

Small-scale turbulence process is critical to material transport and energy exchange in estuaries. Due to the limitation of traditional observation methods, observation of turbulence vertical profiles in relatively shallow areas is scarce, which limits the study of estuarine turbulence processes. In this study, a 5-beam Signature 1 000 kHz acoustic Doppler current profiler (Nortek Signature 1 000 kHz AD2CP) was used to observe the turbulence vertical profiles in the Changjiang (Yangtze) River estuary, and low-noise, high-frequency turbulence parameters vertical profiles were obtained. The data were compared with the synchronous observation results from an Acoustic Doppler Velocimeter (ADV). The comparison shows that the most crucial parameters of the near-bottom boundary layer, such as friction velocity u_*, drag coefficient C_d, and Reynolds stress S_R, obtained by AD2CP and ADV are basically consistent. Bottom friction and wave energy are the main sources of turbulent kinetic energy. Non-local equilibrium is found in turbulence vertical structure. The buoyancy flux caused by temperature and salinity gradient, convection, pulse pressure work, and viscous transport caused by strong wave action are the main factors of the non-local equilibrium of turbulence vertical structure in the Changjiang River estuary.