兰庭飞,吴 昊,唐杰平,李占海,汪亚平.基于新型高频声学多普勒流速剖面仪的河口近底部边界层观测初探[J].海洋通报,2019,(6):640-649
基于新型高频声学多普勒流速剖面仪的河口近底部边界层观测初探
A preliminary study on in situ bottom boundary layer measurement near the seabed of estuaries by using a novel high-frequency Acoustic Doppler Current Profiler
投稿时间:2019-07-13  修订日期:2019-09-23
DOI:
中文关键词:  底边界层  AD2CP  ADV  切应力  长江口
英文关键词:bottom boundary layer  AD2CP  ADV  shear stress  Yangtze River estuary
基金项目:国家自然科学基金“杰出青年科学基金”项目 (41625021);上海市教育委员会科研创新计划项目 (2019-01-07-00-05-E00027)
作者单位E-mail
兰庭飞 南京大学 地理与海洋科学学院江苏 南京 210023 qaz404250625@163.com 
吴 昊 南京大学 地理与海洋科学学院江苏 南京 210023  
唐杰平 南京大学 地理与海洋科学学院江苏 南京 210023  
李占海 华东师范大学 河口海岸学国家重点实验室上海 200241  
汪亚平 南京大学 地理与海洋科学学院江苏 南京 210023华东师范大学 河口海岸学国家重点实验室上海 200241 ypwang@nju.edu.cn 
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中文摘要:
      河口物质输运、能量交换与底边界层内的水动力过程密切相关,底边界层参数 (如切应力、拖曳系数) 的确定至关重要。挪威 Nortek公司生产的新型声学多普勒流速剖面仪 AD2CP相比传统 ADCP具有高频、低噪的优点,可用于高 频 (16Hz) 流速剖面观测,而被广泛应用于底边界层观测的 ADV只能测量单点高频流速。本文采用 AD2CP在长江口南槽最大浑浊带区域进行座底式观测,并与同步近底部三脚架上 ADV的观测结果进行对比。结果表明,使用 AD2CP测得的 近底部平均流速与 ADV的测量结果吻合良好;使用惯性耗散法计算了底切应力,基于 ADV的单点高频流速数据计算结果为 2.16*10-2~5.69*10-1 N/m2,基于 AD2CP的结果为 2.09*10-2~4.26*10-1 N/m2,二者范围大致相当。在此基础上,基于AD2CP数据计算出摩阻流速为 4.55*10-3~2.06*10-2 m/s、底拖曳系数范围为 1.84*10-4~2.49*10-3,与 ADV的计算结果基本一致。此外,由于 AD2CP可以获得高频的流速剖面数据,优于单点 ADV,具备观测近底部边界层参数和边界层内湍流剖面的潜力。
英文摘要:
      Since the material transport and energy exchange in estuary are closely related to the physical processes in the bottom boundary layer (BBL), it is necessary to accurately determine the BBL parameters (e.g. bottom shear stress and drag coefficient). The Nortek's new Acoustic Doppler Current Profiler (AD2CP) has the advantages of high frequency, broadband and low Doppler noise compared with the traditional ADCP, it can be used in measuring high-frequency (16 Hz) velocity profile. The acoustic Doppler velocimeters (i.e. ADV) is widely used in BBL measurements, however it can only measure high-frequency velocity at a single point. Therefore, we applied an AD2CP in the turbidity maximum zone in South Channel of the Changjiang (Yangtze) River estuary, comparing with an ADV near seabed, by deployment of bottom tripods. The results show that the near seabed along-channel velocity of AD2CP agrees well with that of ADV. Based on high-frequency velocity, we used inertial subrange method to calculate the bottom shear stress. Result calculated from ADV忆s data is during 2.16*10-2-5.69*10-1 N/m2, and that from AD2CPs data is during 2.09*10-2-4.26*10-1 N/m2, they are relatively equivalent. Besides,according to the result calculated from the data measured by AD2CP, the friction velocity range is 4.55*10-3-2.06*10-2 m/s,the bottom drag coefficient range is 1.84伊10-4 ~ 2.49*10-3, which are consistent with those measured by ADV. In addition,according to the AD2CP can be used in observing high-frequency velocity profile, which is better than ADV, has excellent potential for BBL observation and measuring turbulence profile
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