Design and deployment of an infrared video monitoring system on an estuarine river
Kara M. Koetje, US Naval Research Laboratory, Washington, DC, United States, Margaret L Palmsten, US Naval Research Laboratory, Stennis Space Center, MS, United States and Shawn R Harrison, U.S. Naval Research Laboratory, Ocean Sciences Division, Stennis Space Center, United States
Abstract:
We have developed a next-generation, long-term monitoring station using a long-wave infrared (LWIR) camera. The objective of the system is to expand the spatial and temporal scales of LWIR data records in nearshore and riverine environments. The system uses an uncooled microbolometer with a thermal resolution of <40 mK and captures a 50° field-of-view at 30 Hz. The system is controlled by a small form factor computer that transfers image data through Gigabit Ethernet communication and can be remotely accessed through a cellular modem. An air-conditioned enclosure makes this system capable of withstanding harsh conditions and is adaptable to a range of coastal and riverine environments.
This system was deployed on the Pearl River in Mississippi, a tidally influenced river that empties into the Mississippi Sound, near the location of USGS stream gage station 02492620. Images of the river surface reveal turbulence-generated thermal gradients that advect with the flow. The propagation of this surface signature has been used to quantify surface velocities and may be used to estimate discharge and water depth. This work seeks to estimate mean surface currents over fall 2019 using three methods: particle image velocimetry (PIV), a spectral method, and a feature-tracking algorithm that utilizes Particle TrackingVelocimetry (PTV) techniques. These techniques are validated using in-situ velocimetry data, surface drifter observations, and collocated unoccupied aircraft system (UAS) imagery.
