School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, 219 Ningliu Rd, Nanjing, 210044, China.
Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, 219 Ningliu Rd, Nanjing, 210044, China.
Environ Sci Pollut Res Int. 2021 Sep;28(33):45506-45518. doi: 10.1007/s11356-021-13810-z. Epub 2021 Apr 18.
Vertical eddy diffusivity (VED) is used to quantify the vertical mixing of water column, which has a profound influence on the evolution of aquatic ecosystems. Based on half-hourly water temperature measured at -20 cm and -150 cm depths from 2015 to 2017 at stations of Pingtaishan (PTS), Dapukou (DPK), Bifenggang (BFG), and Xiaoleishan (XLS) in Taihu Lake, the daily average VED is calculated according to the phase lag of water temperature series at two depths. The temporal and spatial features and possible evolution characters of vertical turbulences are then deliberated. The results show that the VED in Taihu Lake varies by several orders of magnitude. The weak VED exhibits stronger spatial heterogeneity and high frequency characteristics and vice versa for the strong VED. The VED in the center region of the lake is stronger, in comparison to bay areas. On seasonality, the VED is the strongest in winter, moderate in spring and autumn, and the weakest in summer. Analyses show that solar radiation and wind forcing are the key meteorological factors regulating VED changes, with the solar effect somewhat stronger than wind. It is also discussed potential roles of vertical mixing in cyanobacteria becoming dominant population in Taihu Lake.
垂直涡动扩散系数（VED）用于量化水柱的垂直混合，这对水生态系统的演化有深远影响。基于 2015 年至 2017 年在太湖的平山（PTS）、大浦口（DPK）、避风港（BFG）和小雷山（XLS）站每半小时测量的-20cm 和-150cm 水深的水温数据，根据两个深度的水温序列的相位滞后计算出日平均 VED。然后讨论了垂直湍动的时空特征和可能的演化特征。结果表明，太湖的 VED 变化幅度可达几个数量级。弱 VED 表现出更强的空间异质性和高频特征，而强 VED 则相反。与港湾地区相比，湖泊中心区域的 VED 更强。在季节性方面，VED 在冬季最强，春季和秋季适中，夏季最弱。分析表明，太阳辐射和风生强迫是调节 VED 变化的关键气象因素，太阳效应略强于风。还讨论了垂直混合在太湖蓝藻成为优势种群中的潜在作用。
