Parameterisation of the vertical transport in a small thermally stratified lake
Parameterisation of the vertical transport in a small thermally stratified lake
复制标题
小型热分层湖中垂直传输的参数化
DOI：
10.1007/s00027-006-0827-4
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发表时间：
2007
期刊：
影响因子：
2.4
通讯作者：
J. Ilmberger
中科院分区：
文献类型：
--
作者：
C. Rohden;K. Wunderle;J. Ilmberger
摘要。研究了小型富营养化湖泊的垂直输送。研究地点是德国路德维希港附近上莱茵河地堑中的一个砾石坑湖（800 × 250 m，平均深度9 m，最大深度20 m）。控制混合过程的模式的影响，一个强大的密度分层。从每周测得的温度廓线，我们定量估计的有效垂直输送系数Kz的廓线。在分层区域，Kz处于热传导水平（~1.4·10-7 m2/s）。在接近湖底时，我们发现Kz的特征性增加值高达10−5 m2/s。使用底部安装的1,200 kHz-ADCP，我们进行了速度测量，具有高的垂直和时间分辨率（0.2至0.4米和5分钟，分别）的水平电流。使用这些水平流数据和稳定性配置文件，理查森数进行了分析，为期5周，在夏季分层。电流和垂直扩散系数的同时测量，使我们能够检查给定的参数化KZ（Ri），并讨论其适用性的调查系统。
Abstract.Vertical transport in a small eutrophic lake was investigated. The study site is a gravel pit lake in the Upper Rhine Graben near Ludwigshafen, Germany (800 × 250 m, mean depth 9 m, maximum depth 20 m). The governing mixing processes show patterns influenced by a strong density stratification. From weekly measured temperature profiles, we quantitatively estimated profiles of effective vertical transport coefficients Kz. In the stratified regions, Kz is at the level of heat conduction (~1.4·10-7 m2/s). Towards the lake bottom, we found a characteristic increase of Kz to values up to 10−5 m2/s. Using a bottom-mounted 1,200 kHz-ADCP, we performed velocity measurements with a high vertical and temporal resolution (0.2 to 0.4 m and 5 min, respectively) of the horizontal currents. Using these horizontal flow data and stability profiles, Richardson numbers were analysed for a period of 5 weeks during summer stratification. The simultaneous measurements of currents and vertical diffusion coefficients allowed us to check a given parameterisation of Kz(Ri) and to discuss its applicability to the investigated system.