Theodore Langhorst's research while affiliated with University of North Carolina at Chapel Hill and other places

Publications (15)

Article
Full-text available
Areas of lakes that support emergent aquatic vegetation emit disproportionately more methane than open water but are under‐represented in upscaled estimates of lake greenhouse gas emissions. These shallow areas are typically less than ∼1.5 m deep and can be detected with synthetic aperture radar (SAR). To assess the importance of lake emergent vege...
Article
Full-text available
To help store water, facilitate navigation, generate energy, mitigate floods, and support industrial and agricultural production, people have built and continue to build obstructions to natural flow in rivers. However, due to the long and complex history of constructing and removing such obstructions, we lack a globally consistent record of their l...
Article
Optical backscatter sensors (OBSs) are commonly used to measure the turbidity, or light obscuration, of water in fresh and marine environments and various industrial applications. These turbidity data are commonly calibrated to yield total suspended solids (TSS) or suspended sediment concentration (SSC) measurements for water quality, sediment tran...
Preprint
Optical backscatter sensors (OBSs) are commonly used to measure the turbidity, or light obscuration, of water in fresh and marine environments and various industrial applications. These turbidity measurements are commonly calibrated to yield total suspended solids (TSS) or suspended sediment concentration (SSC) measurements for water quality, sedim...
Article
Full-text available
In situ river discharge estimation is a critical component of studying rivers. A dominant method for establishing discharge monitoring in situ is a temporary gauge, which uses a rating curve to relate stage to discharge. However, this approach is constrained by cost and the time to develop the stage‐discharge rating curve, as rating curves rely on...
Article
Full-text available
To advance monitoring of surface water resources, new remote sensing technologies including the forthcoming Surface Water and Ocean Topography (SWOT) satellite (expected launch 2022) and its experimental airborne prototype AirSWOT are being developed to repeatedly map water surface elevation (WSE) and slope (WSS) of the world’s rivers, lakes, and r...
Article
Full-text available
Plain Language Summary In recent years, imagery retrieved from Earth‐observing satellites has improved in quality and become more widely available. We can use the improved satellite imagery to observe the Earth's surface in entirely new ways. One potential application is to identify and map dams and other river obstructions that represent disturban...
Article
Full-text available
The airborne AirSWOT instrument suite, consisting of an interferometric Ka-band synthetic aperture radar and color-infrared (CIR) camera, was deployed to northern North America in July and August 2017 as part of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE). We present validated, open (i.e., vegetation-free) surface water masks produced f...
Article
The Surface Water and Ocean Topography Mission (SWOT) will generate global, spatially continuous maps of water surface elevation and extent for large inland water bodies when it launches in 2021. We present an analysis of water surface elevation, width, and bathymetry timeseries data from a medium-sized (average annual discharge 14 m³/s) river to e...
Article
Full-text available
Existing publicly available digital elevation models (DEMs) provide global-scale data but are often not precise enough for studying processes that depend on small-scale topographic features in rivers. For example, slope breaks and knickpoints in rivers can be important in understanding tectonic processes, and riffle-pool structures are important dr...

Citations

... Can useful analogies for sea level rise can be drawn from sustained record high water levels on the Laurentian Great Lakes (Gronewold and Rood, 2019)? Once-scarce measurements of coastal systems are now pouring in thanks to advances in remote sensing Vos et al., 2019b;Gawehn et al., 2021), cheaper field sensors (Eidam et al., 2021), albatross-based wave observations (Uesaka et al., 2022), crowd-sourcing or citizen science , and especially open data policies (Kinkade and Shepherd, 2021). Some of the latest generation of coastal models improve performance by reducing complexity Leijnse et al., 2021) or instead by explicitly seeking to capture complex system dynamics Bamunawala et al., 2021). ...
... In some situations, labels can be assigned automatically-e.g., merging time-stamped images with time-stamped sensor data (e.g., Buscombe & Carini, 2019;Buscombe et al., 2020). But most of the time, labeling cannot be done programmatically and instead requires human interpretation (e.g., Ellenson et al., 2020;Liu et al., 2014;Buscombe & Ritchie, 2018;Morgan et al., 2019;Yang et al., 2021). ...
... To do this accurately, the scales of the lake levels were matched based on GPS elevation data taken in the field during gauge installation. GPS data were recorded at a rate of one measurement per second using a high-precision Septentrio PolaRx-5 receiver (Leuven, Belgium) that was floated on a small raft [40] for one hour immediately adjacent to the gauge. ...
... Despite this dam quantity, GOODD provides no other attribute information. Another inventory, the Global River Obstruction Database (GROD) (Whittemore et al., 2020;Yang et al., 2022), located more than 30 500 flow obstructions along rivers wider than 30 m as mapped in the Global River Width from Landsat (GRWL) database (Allen and Pavelsky, 2018). The current attributes are mainly limited to obstruction types such as locks, weirs, and multiple types of dams. ...
... AirSWOT carries a SWOTlike Ka-band instrument (KaSPAR), which operates with two swaths (0 to 6° and 4 to 25° incidence angles), and a colourinfrared camera with 1-m spatial resolution. So far, AirSWOT has been used to validate the near nadir-looking Ka-band bistatic interferometry SAR instrument concept for measuring WSE [15][16] [17], and in estimating river discharge [18] and water masks [19]. Validation of AirSWOT measurements was first accomplished by Altenau et al. [15] by comparing the water surface elevation and slope to in-situ data on the Tanana River (Yukon, Alaska). ...
... uniform. In particular, it has been utilised in efforts to derive bathymetry and thereby discharge 122 from space Gleason et al., 2017), and its applicability has been 123 investigated in this context (Tuozzolo et al., 2019). However, the applicability of Manning's 124 equation to estimate flow depths in large multichannel rivers is not well evaluated, and thus 125 forms the objective of this paper. ...
... IET Image Processing published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology the surface water and ocean topography (SWOT) mission was proposed, which was jointly developed by the USA and France [7,8]. To promote the development of SWOT, researchers have used airborne and simulated SWOT data to collect water surface elevation and slope [9][10][11], while others have focused on river reach definition strategies [12] and the impact of radar layover [13]. ...