Near Surface Spatial Water Quality Data Matched with Satellite Imagery and Discrete Phytoplankton Data in the Lower Hudson River New York, 2021-2023

This data release contains phytoplankton, water-quality, and satellite data from thirteen surveys along the lower Hudson River, extending from Yonkers to Troy, New York. Data were collected between August 2021 and October 2023. These surveys included continuous water-quality measurements collected at 10-second intervals using a multiparameter sonde deployed in a boat-mounted flow-through cell. In addition, up to 10 discrete water samples were collected during each survey near established monitoring stations along the river. The multiparameter sonde was used to measure the following water-quality parameters: temperature, specific conductance, dissolved oxygen, pH, turbidity, fluorescence of chlorophyll, fluorescence of phycocyanin, and fluorescent dissolved organic matter. In-situ sonde measurement locations were matched with near-coincident Sentinel-2 satellite imagery to produce a dataset to train and evaluate empirical models of remotely sensed chlorophyll fluorescence. Discrete samples were sent for phytoplankton identification and enumeration by image flow cytometry at a certified laboratory. Additional details regarding data acquisition, data processing, and chlorophyll fluorescence modeling are provided in Salls and others (2025).