Browsing by Author "Cretaux, Jean-Francois"

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    Advancing Field-Based GNSS Surveying for Validation of Remotely Sensed Water Surface Elevation Products
    Pitcher, Lincoln H.; Smith, Laurence C.; Cooley, Sarah W.; Zaino, Annie; Carlson, Robert; Pettit, Joseph; Gleason, Colin J.; Minear, J. Toby; Fayne, Jessica V.; Willis, Michael J.; Hansen, Jasmine S.; Easterday, Kelly J.; Harlan, Merritt E.; Langhorst, Theodore; Topp, Simon N.; Dolan, Wayana; Kyzivat, Ethan D.; Pietroniro, Al; Marsh, Philip; Yang, Daqing; Carter, Tom; Onclin, Cuyler; Hosseini, Nasim; Wilcox, Evan; Moreira, Daniel; Berge-Nguyen, Muriel; Cretaux, Jean-Francois; Pavelsky, Tamlin M. (Frontiers, 2020-11-23)
    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 reservoirs. However, the vertical accuracies of these novel technologies are largely unverified; thus, standard and repeatable field procedures to validate remotely sensed WSE and WSS are needed. To that end, we designed, engineered, and operationalized a Water Surface Profiler (WaSP) system that efficiently and accurately surveys WSE and WSS in a variety of surface water environments using Global Navigation Satellite Systems (GNSS) time-averaged measurements with Precise Point Positioning corrections. Here, we present WaSP construction, deployment, and a data processing workflow. We demonstrate WaSP data collections from repeat field deployments in the North Saskatchewan River and three prairie pothole lakes near Saskatoon, Saskatchewan, Canada. We find that WaSP reproducibly measures WSE and WSS with vertical accuracies similar to standard field survey methods [WSE root mean squared difference (RMSD) ∼8 cm, WSS RMSD ∼1.3 cm/km] and that repeat WaSP deployments accurately quantify water level changes (RMSD ∼3 cm). Collectively, these results suggest that WaSP is an easily deployed, self-contained system with sufficient accuracy for validating the decimeter-level expected accuracies of SWOT and AirSWOT. We conclude by discussing the utility of WaSP for validating airborne and spaceborne WSE mappings, present 63 WaSP in situ lake WSE measurements collected in support of NASA’s Arctic-Boreal and Vulnerability Experiment, highlight routine deployment in support of the Lake Observation by Citizen Scientists and Satellites project, and explore WaSP utility for validating a novel GNSS interferometric reflectometry LArge Wave Warning System.
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    Lake-TopoCat: a global lake drainage topology and catchment database
    Sikder, Md Safat; Wang, Jida; Allen, George H.; Sheng, Yongwei; Yamazaki, Dai; Song, Chunqiao; Ding, Meng; Cretaux, Jean-Francois; Pavelsky, Tamlin M. (Copernicus, 2023-08-08)
    Lakes and reservoirs are ubiquitous across global landscapes, functioning as the largest repository of liquid surface freshwater, hotspots of carbon cycling, and sentinels of climate change. Although typically considered lentic (hydrologically stationary) environments, lakes are an integral part of global drainage networks. Through perennial and intermittent hydrological connections, lakes often interact with each other, and these connections actively affect water mass, quality, and energy balances in both lacustrine and fluvial systems. Deciphering how global lakes are hydrologically interconnected (or the so-called "lake drainage topology") is not only important for lake change attribution but also increasingly critical for discharge, sediment, and carbon modeling. Despite the proliferation of river hydrography data, lakes remain poorly represented in routing models, partially because there has been no global-scale hydrography dataset tailored to lake drainage basins and networks. Here, we introduce the global Lake drainage Topology and Catchment database (Lake-TopoCat), which reveals detailed lake hydrography information with careful consideration of possible multifurcation. Lake-TopoCat contains the outlet(s) and catchment(s) of each lake; the interconnecting reaches among lakes; and a wide suite of attributes depicting lake drainage topology such as upstream and downstream relationship, drainage distance between lakes, and a priori drainage type and connectivity with river networks. Using the HydroLAKES v1.0 (Messager et al., 2016) global lake mask, Lake-TopoCat identifies ĝ1/4ĝ1.46 million outlets for ĝ1/4ĝ1.43 million lakes larger than 10ĝha and delineates 77.5×106ĝkm2 of lake catchments covering 57ĝ% of the Earth's landmass except Antarctica. The global lakes are interconnected by ĝ1/4ĝ3 million reaches, derived from MERIT Hydro v1.0.1 (Yamazaki et al., 2019), stretching a total distance of ĝ1/410×106ĝkm, of which ĝ1/4ĝ80ĝ% are shorter than 10ĝkm. With such unprecedented lake hydrography details, Lake-TopoCat contributes towards a globally coupled lake-river routing model. It may also facilitate a variety of limnological applications such as attributing water quality from lake scale to basin scale, tracing inter-lake fish migration due to changing climate, monitoring fluvial-lacustrine connectivity, and improving estimates of terrestrial carbon fluxes. Lake-TopoCat is freely accessible at 10.5281/zenodo.7916729 (Sikder et al., 2023).