DOI: 10.5066/p14ex8to
title: Hyperspectral image transects and field measurements of reflectance, visible dye concentration, and flow velocity acquired during a tracer experiment on the Missouri River near Lexington, MO, on May 11, 2024

description: This data release includes several types of remotely sensed data and field measurements acquired during a tracer experiment performed on the Missouri River near Lexington, Missouri, on May 11, 2024. One of the primary goals of this study was to assess the feasibility of inferring concentrations of a visible dye (Rhodamine WT) in a large, highly turbid natural river channel using data from a Uncrewed Aircraft Systems (UAS)-based hyperspectral imaging system. Previous research on remote sensing of tracer dye concentrations demonstrated the ability to obtain moderately precise concentration estimates from standard red-green-blue (RGB) video and orthophotos and this experiment allowed us to evaluate the hypothesis that more detailed spectral information could enable concentrations to be inferred with greater accuracy and precision. The broader objective motivating tracer studies along the Missouri River is to gain insight regarding the dispersion processes that influence the movement and survival of endangered sturgeon larvae.
This data release consists of five child items that provide access to various data sets obtained during this experiment:

Digital orthophotos acquired from a fixed-wing crewed aircraft during the tracer experiment to serve as background reference images for the other data sets.
Field measurements of flow velocity obtained using an acoustic Doppler current profiler deployed from a boat along two channel cross sections, one above and one below the transect captured by the hyperspectral imaging system.
In situ measurements of Rhodamine WT dye concentration collected by two sondes, one deployed from a boat as the field spectra were acquired and the other attached to a fixed buoy located within the spatial footprint of the hyperspectral images.
Field spectra recorded along a channel cross section as the plume of Rhodamine WT dye passed by. The data consist of reflectance measurements obtained above the water surface over the wavelength range from 400-900 nm.
Hyperspectral image transects acquired from a stationary UAS hovering above the river during the dye release during four separate flights, along with the trajectory information and supporting files for each flight.

Please refer to the metadata files included along with each child item for further details about each of these data sets. Overall, these data were used to assess the potential for estimating tracer dye concentrations in turbid rivers from UAS-based hyperspectral image data.

In addition, this data release includes MATLAB source code associated with a manuscript titled "Hyperspectral Image  Transects during Transient Events in Rivers (HITTER): Framework development and application to a tracer experiment on the Missouri River, USA." A total of eight *.m files are provided in a separate child item to illustrate how the HITTER approach is implemented within the context of this particular case study on the Missouri River, and seven of the *.m files are general functions that could be applied to other, similar data sets with appropriate modifications of input parameters and file paths.