| dc.description.abstract | Turbulence is a random phenomenon and necessary for energy exchanging and momentum transport in fluid flows. In particularly, in the coastal reef region, turbulent flows plays an important role to uptake nutrients for the ecosystem and control the sediment transports. Thus, study of turbulent characteristics is important in coastal ecosystem area as algal reefs. In this research, we try to observe the turbulent flows in the intertidal reef region through statistical quantities using velocity measurements. The field experiment was deployed at site G1-2 of Datan reef located in the northwest coast of Taiwan. Specifically, we applied the variance method to estimate the Reynolds stress using the Nortek ADCP signature 1000. The results were then compared to the stress computed from the data of three ADVs. The results of the Reynolds stresses estimated from ADCP are overestimated compared to the ADVs. These overestimations are caused by the motions of wave orbital velocities induced bias for the covariance of the beams velocity. Indeed, the results showed that the cross-shore (u′w′) ̅ component coincided with the wave direction gives larger overestimations compared to the along-shore (v′w′) ̅ component that has less wave affection. The shear velocity estimated from the Reynolds stress of the variance method is also overestimated (double larger) compare to the results of ADV3. However, the shear velocity estimated using another method, which is the log-fitting method applied for combined measurements of ADVs and ADCP, gives very good correlation with the ADV3’s estimation. Besides, to observe the balance of TKE budget, we computed the profile of TKE production using the Reynolds stress from ADCP. Then, we applied the structure function for spatial profile of vertical velocity measured by the high-resolution beam of the ADCP to estimate the TKE dissipation rate ε. Correlation of TKE production rate and TKE dissipation rate ε showed the balance of two quantities. Even so, the TKE production need to be re-consider because it has larger order of magnitude compared to previous studies deployed in similar environment. In contrast, ε not only gives approximated values compare to previous studies, but also gives good correlation to the ratio of u_*^3/κz in bursts that qualified the log-fitting followed assumption of P-ε balance. | en_US |