NUSO 2023 Research Missions

Monitoring Topographic, Vegetation, and Habitat Change in the Yosemite National Park

The NUSO partnered with a team of USGS scientists and the National Park Service (NPS) in June and November 2023 to collect high-resolution UAS lidar datasets and photogrammetric imagery to support an ongoing restoration and rehabilitation project to re-establish the Ackerson Meadow to a native wetland environment.

Ackerson Meadow, one of the largest mid-elevation meadows in the Sierra Nevada, is a newly acquired addition to Yosemite National Park. It is an ecologically and regionally critical wildlife corridor and an important habitat for the State’s endangered great Grey Owl and Little Willow Flycatcher, as well as a suite of additional at-risk wildlife species. It was purchased from private ownership in 2016 and donated to Yosemite by a coalition including the Trust for Public Lands, National Park Trust, Yosemite Conservancy, and American Rivers. A large gully network, up to 3 miles long, 14 feet deep, and 100 feet wide has drained 90 acres of wetlands in the meadow complex and is actively eroding an additional 100 acres of remaining wetlands and wet meadow habitat. The gully network is likely a result of over a century of landscape manipulation including domestic water diversion, farming, ranching, and timber harvest. Yosemite National Park and Stanislaus National Forest have partnered with American Rivers and Yosemite Conservancy to implement actions that reduce erosion and restore wetland functionality at Ackerson Meadow. These actions include filling eroded gullied with soils and sediment from nearby locations and revegetating the restored area. Source: NPS Ackerson Meadow Restoration Project 

NUSO scientists have collected high-resolution UAS lidar datasets and photogrammetric imagery of the Main and South Ackerson Meadows as part of an effort to monitor the restoration with a time series of detailed topography, vegetation, and habitat structure. UAS data collections were completed for pre-restoration work in June 2023 and for the early restoration phase in November 2023. Additional fieldwork collections are planned for post-restoration (native revegetation) in 2024, and further monitoring when the wetland is fully restored in 2025.

Study Points of Contact:
Stephen (Steve) DeLong, Supervisory Research Geologist
USGS Southwest Region

Mark Bauer, Geographer
USGS NUSO, Geosciences and Environmental Change Science Center

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Evaluating the Potential of UAS Lidar for 3DEP Validation

In September 2023, the NUSO collected UAS lidar at parks in and nearby Fort Collins Colorado to test methods of validation for the EROS 3DEP Technology Research and Assessment task.  The data will be analyzed by the EROS calibration group to determine the accuracy, precision, and efficiency of UAS lidar compared to traditional terrestrial lidar surveying methods.

The 3D Elevation Program (3DEP), managed by the USGS National Geospatial Program (NGP), systematically acquires nationwide airborne lidar data to provide consistent, high-resolution topographic elevation data across the United States. 3DEP typically includes lidar data collected during leaf-off timeframes to obtain a clearer view of topography. 

The U.S. Department of Agriculture (USDA) Farm Production and Conversation Business Center (FPAC-BC) is the largest 3DEP funding partner and also administers the National Agriculture Imagery Program (NAIP). NAIP airborne imagery is typically collected during the peak growing season which features leaf-on vegetation conditions. 

FPAC-BC funded dual sensor pilot studies to investigate the collection of airborne imagery and lidar in a single aircraft. This simultaneous collection could reduce data collection costs for the 3DEP and NAIP programs. Lidar and imagery are typically collected at different aircraft speeds and altitudes and collected at various seasons. To understand the accuracy and quality of the lidar data being collected in these dual sensor collections, especially in vegetated areas during leaf-on conditions, USGS EROS has collected survey grade GNSS and total station measurements, along with terrestrial lidar for validation in areas including Colorado that have been mapped using this dual-sensor payload. 

Terrestrial lidar systems can yield highly precise and accurate positional data, but the data is resource-intensive to collect in the field and each scan captures a small area at a time from its tripod location. To supplement the traditional terrestrial lidar for 3DEP validation, the USGS NUSO collected UAS lidar data at parks within and near the city of Fort Collins, Colorado. USGS EROS is evaluating the accuracy and quality of UAS lidar data and comparing it to terrestrial data at Spring Canyon Park, Rolland Moore Park, and Lory State Park. UAS lidar has the potential to scale up elevation data validation efforts across larger areas compared to terrestrial lidar systems.

Learn more about the USGS 3D Elevation Program 

Study Point of Contact:
Jeff Irwin, Geographer
USGS Earth Resources Observation and Science (EROS) Center

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UAS Hyperspectral Crop Field Mapping in California

NUSO scientists used UAS to collect hyperspectral imagery in August 2023 to serve as an intermediate scale between field- and satellite-based observations to help build crop classification models for ongoing remote sensing research to monitor globally dominant agricultural crops.

Researchers at the USGS Western Geographic Science Center are studying ways to assess crop productivity, health, yield, lignin and cellulose content using spaceborne hyperspectral systems including German DLR Earth Sensing Imaging Spectrometer (DESIS) and Environmental Mapping and Analysis Program (EnMAP). A new generation of satellite-based hyperspectral sensors will provide hundreds of bands of spectral remote sensing data from space: German DESIS, EnMAP, and Italian PRecursore IperSpettrale della Missione Applicativa (PRISMA).

Hyperspectral satellites were commissioned in coordination with UAS flights at an altitude of 300 feet above ground level and ground-based spectral measurements collected using an ASD FieldSpec instrument. The NUSO collected hyperspectral image data over a variety of crop fields: cotton, almond, pistachio, grape, rice, and corn. The hyperspectral UAS imagery will be calibrated to reflectance and ortho-rectified for comparison with spaceborne and ground-based observations.

Study Point of Contact:
Itiya Aneece, Research Geographer
USGS Western Geographic Science Center

Additional Information:
New generation hyperspectral sensors DESIS and PRISMA provide improved agricultural crop classifications

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Using UAS to Support Road Condition Inspections on Federal Lands

In cooperation with the U.S. Fish and Wildlife Service (USFWS) and the U.S. Department of Transportation (DOT), the NUSO participated in an August 2023 evaluation at the Alamosa National Wildlife Refuge of UAS equipped with various sensors to collect the information necessary to support automated road distress detection.

In addition to protecting and managing the lands and resources under their jurisdictions, Federal Land Management Agencies (FLMAs) are vitally interested in the maintenance of a public road system that provides access for the use, management, and enjoyment of Federal lands. FLMAs work to ensure that their road construction, maintenance, and operations activities are carried out in ways that minimize impacts on operations while complying with adopted standards and federal law regarding highways. Understanding that roads deteriorate over time due to traffic loading and environmental factors and preventive maintenance can be significantly less expensive than rehabilitation or reconstruction, FLMAs periodically inspect their roadway networks to help minimize the maintenance backlog, while also exploring ways to improve their inspection processes.

Accordingly, the USFWS undertook a research effort with the DOT Volpe National Transportation Systems Center (Volpe Center) to identify opportunities, challenges, and needs related to using UAS to support condition inspections on FLMA roads. Alamosa National Wildlife Refuge in Colorado served as a testbed for applying and assessing UAS concepts reviewed in a literature scan and insights gathered from interviews with subject matter experts.

In coordination with the USFWS and the Volpe Center, NUSO remote pilots participated in a two-day demonstration and evaluation of the YellowScan VX20-100 light detection and ranging (lidar) payload on a UAS for assisting with unpaved road condition inspections at Alamosa. The NUSO led the interagency team in the field in placing ground control points and planning, coordinating, and conducting flight missions; UAS pilots from the Federal Highway Administration’s (FHWA) Office of Federal Lands Highway flew complementary missions with their UAS equipment after NUSO’s missions were flown. Multiple flights were conducted to acquire both lidar and imagery data.

The Volpe Center is tasked to assess whether the presence and severity of road distress on unpaved roads can be discerned via remote sensing techniques to generate a condition rating for a road. The USFWS and Volpe Center team expect to complete a final report for the research project by the end of the calendar year 2023.

Study Points of Contact:
Mark Bauer, Geographer & Remote Pilot
USGS NUSO, Geosciences and Environmental Change Science Center

Peter Tomczik, Transportation Asset Management Coordinator
Branch of Transportation and Data Management, United States Fish and Wildlife Service

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UAS Measurements of Methane in Interior Alaska

In August 2023 the NUSO flew UAS equipped with custom methane-detecting sensors over Interior Alaska to support USGS and U.S. Environmental Protection Agency (EPA) Office of Research and Development research into low-cost ways to measure methane emissions.

As permafrost soils in the Arctic warm and thaw, greenhouse gases including methane are released into the atmosphere. Scientists at the USGS Geology, Minerals, Energy, and Geophysics Science Center are researching low-cost ways to measure methane emissions across these changing ecosystems. Scientists have traditionally monitored methane emissions using ground-based flux towers and surface chambers. While these methods provide valuable data, the measurement techniques are resource intensive and therefore done only in limited areas. A crewed helicopter at low altitude increases personnel risk, has the potential to disturb wildlife, and would have difficulty getting low enough to accurately measure these emissions. UAS, also known as drones, may enable scientists to significantly enhance their data collection capabilities at wetlands across Alaska.

During this mission the NUSO flew UAS equipped with custom methane-detecting sensors utilizing various altitudes and flight patterns at the Bonanza Creek Long-Term Ecological Research Site (BNZ LTER) located approximately 20 km southwest of Fairbanks, Alaska. UAS-based methane observations were collected with two distinctive custom methane-sensing payloads by USGS and EPA researchers for inter-comparison and with fixed tower-based measurements at BNZ LTER.

Study Points of Contact:
Kristen Manies, Ecologist
USGS Geology, Minerals, Energy, and Geophysics Science Center

Brian Gullett, Environmental Engineer
Office of Research and Development, U.S. Environmental Protection Agency

Additional Information:
Arctic Biogeochemical Response to Permafrost Thaw (ABRUPT)

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Radiometric Calibration and Validation Research for Scientific-grade Spectral UAS Imagery

In support of radiometric calibration and validation research at USGS, the NUSO in July 2023 collected multispectral and hyperspectral UAS data at several sites near the Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota.

The EROS Calibration/Validation Center of Excellence (ECCOE) is responsible for the radiometric and geometric characterization and calibration of Landsat satellite instruments. Spaceborne sensors such as those onboard the Landsat satellites are rigorously characterized and calibrated using both laboratory and onboard techniques to generate science-grade data products. Although UAS technologies offer flexible opportunities to capture low-altitude remote sensing data, their low-cost sensors and variable environmental conditions during data collection create challenges for radiometric calibration. Developing UAS calibration protocols and quantifying sources of uncertainty are active areas of research in the remote sensing community.

The NUSO collected AgEagle/MicaSense RedEdge MX-Dual 10-band multispectral and Headwall Nano-Hyperspec 274-band hyperspectral UAS imagery over the course of four days and various environmental conditions (wildfire smoke, partly cloudy, and clear skies). The UAS flights were conducted at approximately 10am, 12pm, and 1-2pm each day to capture different solar geometries. ECCOE scientists measured a series of reflectance targets and a large, vegetated site using handheld spectrometers in close time proximity to the UAS collections and overpasses by Landsat 9 and Sentinel 2B.

The data collected in coordination between the NUSO and ECCOE will enable USGS researchers to explore questions related to calibration panel materials, colors, and sizes for UAS imagery calibration procedures. In conjunction with satellite overpasses, the UAS data collected during this mission may also provide value for satellite data validation studies.

Study Point of Contact:
Jeff Irwin, Geographer & Field Team Lead
EROS Calibration/Validation Center of Excellence

Additional Information:
Guidelines for Calibration of Uncrewed Aircraft Systems Imagery (USGS Open File Report)

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Test and Evaluation of UAS 3D Scan for Bridge Inspection at the Green Mountain Reservoir

The NUSO, along with U.S. Bureau of Reclamation participated in a June 2023 test and evaluation of an uncrewed aircraft’s 3D scan capability for assisting with infrastructure inspections near Heeney, Colorado at the Green Mountain Reservoir.

NUSO researchers are conducting evaluations of UAS to find suitable replacements for the existing Department of the Interior (DOI) UAS fleet. The Skydio X2D is a 4th generation DOI UAS that has sophisticated artificial intelligence algorithms running on the flight controller while also using 360-degree obstacle avoidance cameras. This allows the aircraft to perform fully autonomous photogrammetric missions in confined, GPS-denied environments. The NUSO is testing the Skydio X2D 3D scan capability to create photogrammetric models to assist infrastructure assessment teams at bridges and dams.

Working alongside Civil Engineer Matthew Klein’s team from the Bureau of Reclamation, the NUSO participated in a test and evaluation of the Skydio X2D uncrewed aircraft’s 3D scan capability for assisting with infrastructure inspections near Heeney, Colorado at the Green Mountain Reservoir. NUSO team members placed a series of ground control points and scale bars to assist with the processing of the photogrammetric models. Multiple flights were conducted that focused on the main bridge deck, bridge supports, and bridge substructure. Several visual observers were present including Rich Thurau of the DOI Office of Aviation Services to maintain visual site of the aircraft during the scan. Since these were the first flights using the Skydio in confined spaces, more care was taken to track the aircraft. Matt Chandler, Aaron Begle and Taylor Mitcham from Skydio were also present to assist with 3D scan parameters and provide support. The aircraft performed as advertised with little to no input from the remote pilot during the scan. Independent review of the Skydio imagery showed it is possible to acquire a high-quality camera calibration for the Skydio imaging systems allowing for a highly accurate photogrammetric model.

Learn more about the U.S. Bureau of Reclamation Green Mountain Powerplant

Study Points of Contact:
Todd Burton, Regional Aviation Manager & Remote Pilot
USGS NUSO, Geosciences and Environmental Change Science Center

Mark Bauer, Geographer
USGS NUSO, Geosciences and Environmental Change Science Center

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UAS Multi-scale Remote Sensing for Carbon Sequestration on Public Lands

In May 2023, in coordination with Bureau of Land Management (BLM) and the National Ecological Observatory Network (NEON), the NUSO collected UAS data over two BLM Assessment, Inventory, and Monitoring (AIM) plots at the NEON Moab site to support multi-scale carbon sequestration research on public lands. The UAS data collected included natural color, multispectral, hyperspectral, and lidar to capture diverse information about vegetation and soils.

USGS researchers are studying ways to quantify and manage carbon sequestration across drylands. Although satellites offer global remote sensing coverage and a long-term data record, estimates of aboveground biomass and plant productivity via spectral indices are known to under-perform in drylands. The BLM measures field-based aboveground biomass at AIM sites spread across public lands in the west. However, BLM AIM plots require intensive sampling and offer finite observations over large areas.

The NEON has a long-term monitoring site located on high-desert BLM land 25 miles south of Moab, Utah. In addition to collecting meteorological, soil, vegetation, and wildlife observations, NEON collects and delivers freely available airborne remote sensing data at this site on a semi-annual basis. NEON’s airborne system collects lidar, spectrometer and high-resolution RGB camera data.

UAS provide a high spatial resolution (2-4cm) perspective that can help connect BLM AIM field measurements to airborne and satellite observations. In May 2023, the NUSO coordinated with BLM and NEON to collect field, UAS, and airborne data at the NEON Moab site. NEON collected airborne data at a flight altitude of 1000 meters above ground level (AGL) on April 28. During the following week, the NUSO collected UAS natural color, multispectral, hyperspectral, and lidar data at a flight altitude of 31 meters over two BLM AIM plots that were imaged by the NEON's airborne platform. BLM AIM teams collected field-based measurements of vegetation and soil at these two sites. USGS researchers will link these data sets to inform carbon storage questions on public lands.

Learn more:
Bureau of Land Management (BLM) Assessment, Inventory, and Monitoring (AIM)
National Ecological Observatory Network (NEON)
NEON MOAB site

Study Points of Contact:
Victoria Scholl, Physical Scientist & Remote Pilot
USGS NUSO, Geosciences and Environmental Change Science Center

Sasha Reed, Ph.D., Research Ecologist
Canyonlands Research Station, Southwest Biological Science Center

Brooke Osborne, Professor, Environment & Society
Utah State University

Jason Burgess-Conforti, Monitoring Coordinator/Ecologist
Assessment, Inventory, and Monitoring (AIM), Bureau of Land Management

Additional Information:
Uncrewed Aircraft Systems (UAS) natural color, multispectral, lidar, and hyperspectral remote sensing data products collected at dryland sites 40 km south of Moab, Utah in May 2023 (USGS Data Release)

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UAS Mapping of Pleistocene Fossilized Trackways at the White Sands National Park

In coordination with the NPS, the NUSO collected scientific UAS data in April 2023 at the White Sands National Park to document trackways before erosion erases their existence.

Although White Sands National Park is widely recognized for its wave-like gypsum sand dunes, this national park is also home to the world’s most extensive collection of fossilized footprints from the Pleistocene epoch. These fossilized tracks were left by ice age megafauna including mammoths, giant ground sloths, dire wolves, and even footprints left by humans along the shores of the ancient Lake Otero in the Tularosa Basin. These footprints are the subject of globally significant archeological

 research: The oldest human footprints in North America were recently discovered at White Sands, changing the timeline of human arrival in the Americas by nearly 10,000 years (Bennett et al. 2021).

Soil stability, erosion, moisture, and activity at the nearby White Sands Missile Range pose a threat to these ephemeral fossilized tracks. White Sands National Park personnel are exploring the use of UAS to advance their preservation and applied research capabilities. UAS are scientific tools that could be used to reduce the destructive impact of work around trackway sites and to digitally capture trackways for future studies.

NUSO scientists collected natural color and lidar data at a variety of flight altitudes and spatial scales at multiple sites with known fossilized footprints. Note that the UAS data collected at White Sands National Park is protected and not released publicly. It is being utilized by park personnel for resource protection and preservation. The use of UAS and aircraft is prohibited from flying in the airspace above the park. USGS worked with the National Park Service and White Sands Missile Range to obtain airspace authorizations over the Park within a narrow window of time to conduct this data collection.

Reference:
Bennett, Matthew R., David Bustos, Jeffrey S. Pigati, Kathleen B. Springer, Thomas M. Urban, Vance T. Holliday, Sally C. Reynolds et al. "Evidence of humans in North America during the last glacial maximum." Science 373, no. 6562 (2021): 1528-1531. DOI:10.1126/science.abg7586

Learn more:
National Park Service: Fossilized Footprints
PBS Nova: Ice Age Footprints

Study Point of Contact:
David Bustos, Resource Program Manager
White Sands National Park, Alamogordo, NM

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Gamma Ray Spectrometer Testing and Evaluation

In March 2023 the NUSO started work to learn how to collect UAS high-resolution gamma ray radiometric data in support of mineral resource research conducted by USGS Geology, Geophysics and Geochemistry Science Center (G3SC) geophysicists and funded by the Earth Mapping Resources Initiative (Earth MRI).

USGS geophysicists at the G3SC are engaged in studies of potential mineral resources from both in situ deposits and mining waste and tailings through the USGS Mineral Resources Program, including the Earth MRI effort. Airborne radiometric methods were first developed in the 1970s, primarily to assist with uranium exploration. The development of improved sensors and processing technology has led to new applications such as geologic mapping, mineral resource evaluation, and mining waste characterization (Shah et al. 2020; Shah et al. 2021).

Utilizing UAS technologies to conduct gamma ray radiometric surveys can facilitate a 10-fold or more increase in resolution over airplane or helicopter radiometric surveys because of reduced distance between source and sensor. At the same time, the UAS platform can reduce and potentially eliminate the need for personnel to walk, hike, and climb in unsafe terrain and environments where data collection is required.

The Department of Energy Office of Legacy Management (DOE-LM) maintains calibration facilities where environmental radiation sensors can be evaluated at the Grand Junction Regional Airport (GJT) in Grand Junction, Colorado. These facilities include large, flat concrete pads constructed with known concentrations of radioactive potassium, thorium, and/or uranium which emit gamma rays and are a high-quality calibration source utilized by crewed aircraft. These calibration pads provided a safe, controlled environment for USGS personnel to learn, test, and evaluate handheld gamma ray sensors in addition to a Medusa MS-350 Gamma Ray Spectrometer recently acquired by the NUSO.

The Medusa M-350 is a next-generation lightweight (< 3 kg) CsI sensor that can be used as part of a UAS. In coordination with DOE-LM and GJT, NUSO remote pilots flew a variety of transect spacings, altitudes, and directions over the radioelement calibration pads built into the tarmac at GJT. G3SC researchers also collected static measurements with handheld gamma ray spectrometer instruments to assess radiation at a variety of heights over the calibration pads to compare instruments and readings.

Since this was the first NUSO UAS mission flown over an active airport its successful execution relied on receiving the appropriate permissions and providing extensive communications with the Airport Authority, Tower, FAA personnel, DOE-LM contacts, and aviation safety personnel.

Learn more:
Earth Mapping Resources Initiative (Earth MRI)
USGS Makes $5 million available from the Bipartisan Infrastructure Law for mine waste research (USGS News Release)
Scientists Discover Significant Critical Minerals Potential in Northern Maine (USGS News Release)
U.S. Department of Energy Office of Legacy Management (DOE-LM) Calibration Facilities

Study Points of Contact:
Joe Adams, IT Specialist & Remote Pilot
USGS NUSO, Geosciences and Environmental Change Science Center

Anjana K. Shah, Ph.D., Research Geophysicist
USGS Geology, Geophysics and Geochemistry Science Center

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