Variable physical drivers of near-surface turbulence in a regulated river

This dataset is used to analyze the drivers of near-surface turbulence in large rivers. The data were collected during the measurement campaign conducted at the River Kitinen in Northern Finland (67.3665º N, 26.6230º E) in the summer of 2018. At the study site, the river is 181 m wide, and its flow is regulated by two hydropower stations. These unique data include results of measurements in the river and the atmosphere collected at different locations: a floating platform in the middle of the river, the river bottom, a meteorological mast at the river bank, and a land meteorological tower located at a small distance to the east of the river bank. The river data contain continuous measurements of flow velocity (ADCP, bottom; ADV, platform), water temperature (thermistor chain, river middle), water level (wave recorder, river bank), and photosynthetically active radiation (PAR sensor, platform). The atmospheric data contain continuous measurements of wind speed and direction, air temperature and relative humidity, and incoming shortwave and longwave radiation (river bank mast and land tower). The detailed information about the measurement instruments can be found in the corresponding article “Variable physical drivers of near-surface turbulence in a regulated river”. Rivers are an important source of the greenhouse gases to the atmosphere. The gas exchange at the air-water interface is largely controlled by the near-surface turbulence, which has not been studied in details for large rivers. The idea behind the analysis of these data is to determine the main drivers of the near-surface turbulence in large rivers and their relative importance. To that end, we computed the dissipation rate of turbulent kinetic energy and compared it with the estimates provided by bulk scaling relations and a one-dimensional numerical turbulence model. The results are two-fold. First, all estimation methods are able to accurately predict the dissipation rate. Second, the two main drivers of the near-surface turbulence, namely the bottom friction and the atmospheric forcing, have comparable relative contributions.本数据集用于分析大型河流近地表湍流的驱动因子。数据采集于2018年夏季，采自芬兰北部基蒂内河（River Kitinen，北纬67.3665°，东经26.6230°）的外场测量计划。研究河段河宽181米，其水流受两座水电站调控。这套独特的数据集包含了不同点位采集的河流与大气观测结果：河道中央的浮动平台、河底、河岸处的气象桅杆，以及河岸东侧不远处的陆上气象塔。河流观测数据包含流速（ADCP，河底布设；ADV，平台布设）、水温（热敏电阻链，河道中央布设）、水位（波潮记录仪，河岸布设）以及由平台上的PAR传感器采集的光合有效辐射（Photosynthetically Active Radiation，PAR）的连续观测序列。大气观测数据包含风速与风向、气温与相对湿度，以及入射短波辐射和长波辐射的连续观测结果，观测设备分别部署于河岸气象桅杆与陆上气象塔。关于测量仪器的详细信息可参阅对应论文《Variable physical drivers of near-surface turbulence in a regulated river》。河流是向大气排放温室气体的重要来源。气-水界面的气体交换主要受近地表湍流调控，但目前针对大型河流的近地表湍流尚未得到深入研究。本数据集的分析核心目标为明确大型河流近地表湍流的主要驱动因子及其相对重要性。为此，我们计算了湍流动能耗散率，并将其与整体标度关系（bulk scaling relations）以及一维数值湍流模型得到的估算结果进行对比。研究结果分为两个方面：其一，所有估算方法均可准确预测湍流动能耗散率；其二，近地表湍流的两大主要驱动因子——底摩擦与大气强迫——具有相当的相对贡献。