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NUSO 2022 Research Missions


Mapping snowpack with lidar point clouds

Winter Park and Berthoud Pass, Colorado
Sony R10C natural color image of the Berthoud Pass study site showing a deployed Aeropoint target (black and white square in the upper left)
Sony R10C natural color image of the Berthoud Pass study site showing a deployed Aeropoint target (black and white square in the upper left)

Accurately measuring snow depth is crucial for calculating snow water equivalent (SWE), the amount of water in snow, that plays a key role in estimating snowmelt runoff and the seasonal water amounts that will enter various watersheds.

NUSO researchers are working to develop and verify methods for generating snow-depth maps from UAS collected lidar point cloud data as part of an initiative between the USGS Next Generation Water Observing System (NGWOS) and Colorado Department of Transportation (CDOT). This multi-year initiative is aimed at collecting and comparing on-the-ground snow measurements, taken from snow pits, snow probes, and snow cores, to snow depths derived from remotely sensed data. The ability to utilize UAS data collection for snow-depth measurements could also contribute to the NGWOS goal to cover currently unmonitored watershed areas.

The USGS field team conducted three separate UAS data collects of the Winter Park, Colorado study site in September 2020, February 2021, and April 2021. During each of these missions USGS collected topographic data in a lidar point cloud (LPC) format from a YellowScan VX20-100 lidar payload, a lidar scanner and integrated inertial navigation unit, mounted on a UAS. Natural color imagery was also collected, and ground-based targets were surveyed for control and accuracy validation. After successfully processing the lidar point cloud (LPC) data a bare-earth digital elevation model and a snow-surface model (vegetation removed) were generated. Snow-depth maps were then created by subtracting the bare-earth terrain from the snow-surface model. And as a final product the orthomosaic created from the natural color imagery was used to colorize the LPC data.

Point cloud model of Berthoud Pass showing vegetation (orange) and snow (gray). This model was generated from data collected from a UAS mounted lidar sensor in March 2022.
Point cloud model of Berthoud Pass showing vegetation (orange) and snow (gray). This model was generated from data collected from a UAS mounted lidar sensor in March 2022.
Point cloud model of Berthoud Pass with the vegetation removed to reveal the snow surface colorized based on elevation heights. This model was generated from data collected from a UAS mounted lidar sensor in March 2022.
Point cloud model of Berthoud Pass with the vegetation removed to reveal the snow surface colorized based on elevation heights. This model was generated from data collected from a UAS mounted lidar sensor in March 2022.

In March and April of 2022, NUSO performed new UAS lidar and natural color data collection missions over the Berthoud Pass study site in Colorado. NUSO flew a UAS mounted with the YellowScan Mapper lidar payload with a RGB camera module to enable photogrammetry and colorizing of the point cloud data. Work is currently underway to process the collected data and generate the various maps and models to assist with mapping spatial and temporal variations in snowpack.

USGS Featured Story: Get to know the scientists behind snow to flow: The study of snowmelt in the Western U.S.

Study Point of Contact:
Graham A. Sexstone, PhD, Research Hydrologist
U.S. Geological Survey
sexstone@usgs.gov

Biocrust Remote Sensing

Moab, Utah
Matt Burgess (USGS NUSO) collects RGB imagery from a UAS mounted Ricoh GRII sensor.
Matt Burgess (USGS NUSO) collects RGB imagery from a UAS mounted Ricoh GRII sensor.

Biological soil crusts (biocrusts) are diverse communities of organisms including lichen, moss, and cyanobacteria living on soil surfaces in arid environments around the world. Although biocrusts play important roles in water and carbon cycling, there is great uncertainty and many unanswered questions related to their presence and function. Researchers at the USGS Canyonlands Research Station maintain a long-term biocrust monitoring site near Moab, Utah to study the effects of a warming climate and precipitation changes on biocrust community behavior and composition. Ground-based measurements including soil moisture, biocrust and vegetation species composition, and gas exchange are collected regularly at plots receiving various temperature and watering treatments.

Remote sensing technologies provide opportunities to scale up observations of how biocrusts respond to environmental changes. In February 2022, researchers from the USGS Canyonlands Research Station, USGS Western Geographic Science Center, University of Arizona School of Natural Resources and the Environment, and the USGS National Uncrewed Systems Office (NUSO) teamed up to collect a series of coincident field-based and UAS remote sensing data at the biocrust monitoring plots. The USGS NUSO conducted a series of UAS flights carrying six different sensors to collect natural-color RGB (Ricoh GRII), thermal (Zenmuse XT2), multispectral (MicaSense MX-Dual; MicaSense Altum), and hyperspectral (Resonon Pika-L; Headwall Nano) remote sensing imagery across the extent of the biocrust monitoring plots.

Victoria Scholl (USGS NUSO) and Armin Howell (USGS Canyonlands Research Station) hike to the biocrust monitoring site carrying ground control targets and other equipment.
Victoria Scholl (USGS NUSO) and Armin Howell (USGS Canyonlands Research Station) hike to the biocrust monitoring site carrying ground control targets and other equipment.

Using this imagery, NUSO will generate a series of spectral and structural photogrammetric data products including reflectance orthophotomosaics, digital elevation models, and three-dimensional structure-from-motion point clouds. Ground based measurements collected during the UAS flights included spectral reflectance profiles of land cover types and biocrust/vegetation species, plot-level thermal and RGB images, and gas exchange measurements. Multiple satellite overpasses occurred during the field campaign to enable further cross-scale remote sensing analyses.

Study Points of Contact:
Sasha Reed, Ph.D., Research Ecologist
Canyonlands Research Station, Southwest Biological Science Center
screed@usgs.gov

Miguel Villareal, Ph.D., Research Geographer
NASA AMES-Moffett Field, Western Geographic Science Center
mvillarreal@usgs.gov

Matthew Burgess, Ph.D., UAS Operations / Geospatial Analyst
National Uncrewed Systems Office, Geosciences and Environmental Change Science Center
maburgess@usgs.gov