LISST-SL2 Is Demonstrated in Yangtze River, Wuhan, China
[This article shows an example of river data from a boat; for bridge-lowered data, click here.]
The Yangtze River hydrological facility is located in Wuhan on the western bank. A map of the location can be found here (30°37’41.59″ N 114°19’37.23″ E). With help from personnel at the local station, a research vessel was used to deploy the LISST-SL2. The instrument was lowered into the river to obtain vertical profiles at 3 stations in the cross-section. Full data were recovered. Photos below show the research vessel and ramp.
The ramp and the vessel used for data collection (with flag).
The LISST-SL2 is ready to be lowered into the river (Nathan from China OREs).
1. THE FINAL PRODUCT: DEPTH-AVERAGED CONCENTRATIONS, VELOCITY
These means are computed and displayed by the software immediately after saving the data.
2. DETAILED VIEW: TIME SERIES MODE OF DATA, LISST-SL2 HELD AT 4 DEPTHS.
The operator can see real time data in this mode, i.e. as a time series, or in profile mode (next figure).
3. DETAILED VIEW: VERTICAL PROFILE DISPLAY OF THE SAME TIME SERIES
In this mode of viewing the raw data during acquisition, the vertical structure can be easily seen. Here, one sees the increase in sediment concentration with depth (left panel), the reduction in river velocity as the LISST-SL2 nears bottom (middle panel), and the change in size distribution with depth (right panel). Note that the sand mode becomes the dominant one near bottom. It is to be noted that the fluctuations seen in this data are true variations of sediment concentration and velocity (not measurement ‘noise’). Samplers are unable to capture a meaningful mean value.
The LISST-SL2 is set to launch an era of simpler, economical and more thorough data collection in rivers of the world.
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