UAH hyperspectral drone flights test new tool for UGA marsh grass researchers


The University of Alabama in Huntsville (UAH) Atmospheric Science Department and UAH’s Rotorcraft Systems Engineering and Simulation Center (RSESC) have teamed up to offer University of Georgia scientists a unique drone-gathered data set for their coastal disturbance studies.

Researchers from the UGA Marine Institute are tracking the effects of natural and human-made disturbances on the marsh ecosystems at the National Science Foundation (NSF) funded Georgia Coastal Ecosystems Long Term Ecological Research site on Sapelo Island.

The Marine Institute employs biologists, geographers and atmospheric scientists to study long-term trends that can manifest in many ways, including changes in water quality, river discharge, marsh productivity, and runoff and tidal inundation patterns throughout the estuarine landscape.

“There is a lot of interest in tracking the health of the ecosystems in the salt marshes,” says Dr. Udaysankar Nair, UAH associate professor of atmospheric science.

The brackish water in salt marshes is the birthplace of numerous saltwater species, and marsh grasses provide important ecosystem services such as sediment accumulation erosion control and habitat. The processes by which marsh grasses recover from different disturbances and the degree of their resiliency are key to healthy marine ecosystems.

“They have been tracking those ecosystems and following them for a long time,” Dr. Nair says.

Working with UGA’s Dr. Merryl Alber, project director and professor, and Dr. Deepak Mishra, professor of geography, the UAH team is part of an exploratory effort to determine whether using a hyperspectral imaging camera mounted to a drone can provide UGA scientists with a more detailed look at the marsh grasses and the recovery processes coastal marsh grasses undergo after degrading from natural or human events.

“Our function there is to collect data to determine the different species of grass are in the estuary,” Dr. Nair says.

In the past, species assessments have been conducted on foot, by using NASA satellite data, by airplane and by using a drone that provides four channels of spectral data.

In contrast, UAH’s Unmanned Aerial Vehicle (UAV) delivers 120 channels of spectrum. It’s been dubbed the Hyperspectral Drone Remote Sensing Applications platform, or HYDRA. Casey Calamaio, an RSESC research scientist, is in charge of the drone flights.

“Using HYDRA, we are able to provide a finer scale data field, and with a UAV, we can do that with a lot more efficiency in areas that are of most interest in the salt marshes,” Calamaio says.

The UAH team conducted flights on the island in August. With Dr. Nair and Calamaio was NSF Research Experiences for Undergraduates student Dylan McKelvey, a senior at the University of North Alabama. McKelvey’s research was supported by National Science Foundation award AGS-1757892.

“We were flying a specialized camera and this provided us with a unique opportunity to calibrate the camera in this environment,” Calamaio says.

The team was able to determine times of day to fly for best data collection, as well as assess the effects of water and various terrains and vegetative cover on the quality of data collected by the camera.

“Joining the team at Sapelo Island gave us an interesting case study to define best practices for collecting this kind of low-altitude drone data,” Calamaio says.

Researchers can use the data to determine the types of grass growing, where there is bare soil, where there is salt-laden soil, what grass populations are doing best and areas where the grass has been impacted, among other ecological drivers.

UAH’s involvement was a test bed for future UAV and hyperspectral uses in the UGA research effort.

“Their plan is to see how they do with their drone versus our results,” Dr. Nair says.

He says future integration of a Light Detection and Ranging (LIDAR) sensor into the HYDRA payload will allow the height of vegetation to be measured, so that scientists can see where plants are growing best and which ones are impacted by events.

The Georgia drone flights have broader applications for future UAH drone applications, Dr. Nair said. Following major weather events like hurricanes and tornadoes, ecosystem damage assessments could provide vital specialized data for government-funded researchers monitoring ecological recovery.

“If you have federal aid to any degree, you have to have some kind of an assessment made,” Dr. Nair says.

Calamaio says the experience with the HYDRA is “the beginning of future areas of research and application for RSESC.”

The effort holds promise from an atmospheric science perspective, Dr. Nair says.

“We are hoping that it provides us a gateway to do more of this type of work in a lot of different areas.”