Merritt E. Harlan David M. Bjerklie Jack R. Eggleston Ryan M. Riggs Jacob A. Zwart 20260330 tabular digital data Online (digital release) U.S. Geological Survey https://doi.org/10.5066/P1FE9W9E This dataset contains paired in situ and satellite-derived water surface elevation (WSE) observations compiled to evaluate the accuracy of the Surface Water and Ocean Topography (SWOT) mission water surface elevation data over rivers and lakes. In situ WSE measurements were obtained from the U.S. Geological Survey (USGS), U.S. Bureau of Reclamation (BOR), Environment and Climate Change Canada (ECCC), and the Ministry of the Environment in Quebec. These observations were paired with coincident SWOT Level-2 River and Lake Single Pass (SP) product water surface elevations (Version C & D) collected between January 1, 2023 and December 31, 2025. The dataset includes SWOT data and associated quality flags, gage-observed WSE, and associated metadata. Data are organized by river reach (SWOT data aggregated over a river reach ~ 10 km in length), river node (SWOT data aggregated over a smaller region ~ 200 m in length), and lake data, where SWOT elevations are aggregated over the entire observed lake area. Gage-observed WSE data have been converted to SWOT's vertical datum (Earth Gravitational Model EGM2008) where possible. The compiled tabular outputs support evaluation of SWOT WSE performance across hydrologic conditions, site characteristics, and filtering strategies. A subset of possible SWOT data quality filters and remaining data percentage and accuracy are included as well, supporting a Pareto analysis for these given filters. These data were compiled to assess and characterize the performance of SWOT-derived water surface elevation observations relative to in situ gage measurements. The dataset enables systematic evaluation of SWOT WSE accuracy, including quantification of biases, variability, and sensitivity to quality filtering approaches. By providing paired SWOT and gage observations across 2,662 river and lake sites, this dataset supports validation of satellite elevation products, development of improved filtering strategies, and refinement of SWOT-based hydrologic applications. The data may be used to inform uncertainty characterization, guide best practices for SWOT WSE use in research and operational contexts, and support future development of satellite-derived discharge and water level products. 20230101 20251231 publication date Complete None planned -163.6780 -53.5686 70.2814 28.0847 ISO 19115 Topic Category environment inlandWaters none Surface Water Ocean Topography (SWOT) satellite water surface elevation USGS Thesaurus water resources remote sensing USGS Metadata Identifier USGS:688ce6bdd4be02086276c296 No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons Zero v1.0 Universal (CC0-1.0) public domain dedication and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. USGS - WATER Merritt E Harlan Mendenhall Researcher mailing and physical

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Lakewood CO 80225 (774)641-4099 mharlan@usgs.gov This work was funded by the NASA Terrestrial Hydrology Program (Agency Agreement Tracking number: NNH23OB63A), and the U.S. Geological Survey Hydrologic Remote Sensing Branch. R code was developed to download, merge and format these data, using R version 4.5.2. The data file formats are comma separated values (csv) data, which can be accessed in Microsoft Excel or other spreadsheet software. Frank Greguska Nikki Tebaldi Victoria McDonald Cassie Nickles James Wood 20250814 1.6.5 application/service online Zenodo Frank Greguska, Nikki Tebaldi, Victoria McDonald, Vanesa, Cassie Nickles, & James Wood. (2025). podaac/hydrocron: 1.6.5 (1.6.5). Zenodo. https://doi.org/10.5281/zenodo.16877776 https://doi.org/10.5281/zenodo.16877776 U.S. Geological Survey 20160101 application/service online U.S. Geological Survey http://dx.doi.org/10.5066/F7P55KJN Laura DeCicco Robert Hirsch David Lorenz Jordan Read Jordan Walker Lindsay Platt David Watkins David Blodgett Mike Johnson Aliesha Krall Lee Stanish Joseph Zemmels Elise Hinman Michael Mahoney 20250101 application/service online U.S. Geological Survey DeCicco, L.A., Hirsch, R.M., Lorenz, D., Watkins, W.D., Johnson, M., 2025, dataRetrieval: R packages for discovering and retrieving water data available from Federal hydrologic web services, v.2.7.20, doi:10.5066/P9X4L3GE https://doi.org/10.5066/P9X4L3GE Jet Propulsion Laboratory 20250304 Revision A publication online Jet Propulsion Laboratory JPL D-109532, Revision A, “SWOT Science Data Products User Handbook,” Jet Propulsion Laboratory Internal Document, Pasadena, CA, 2025. https://archive.podaac.earthdata.nasa.gov/podaac-ops-cumulus-docs/web-misc/swot_mission_docs/D-109532_SWOT_UserHandbook_RevA_20250311_sig-final.pdf Sam J. Albers 20171214 publication online The Journal of Open Source Software Albers, S. (2017). Tidyhydat: Extract and Tidy Canadian Hydrometric Data. The Journal of Open Source Software, 2(20). https://doi.org/10.21105/joss.00511 https://doi.org/10.21105/joss.00511 NOAA's National Geodetic Survey 20250917 v4.8 application/service online NOAA https://vdatum.noaa.gov/ Environment and Climate Change Canada 20221026 application/service https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/tools-outils/trx.php Quebec Ministry of the Environment 20230118 1.3 application/service https://www.cehq.gouv.qc.ca/atlas-hydroclimatique/stations-hydrometriques/index-en.htm U.S. Bureau of Reclamation 20251029 2.15.4 publication https://data.usbr.gov/rise-api The accuracy of the attributes in this dataset reflects the quality of the original data sources and the processing steps used to compile and pair the observations. SWOT water surface elevation observations were obtained directly from NASA Surface Water and Ocean Topography (SWOT) mission data products as described in Processing Step 2. No additional quality control filtering was applied to the SWOT observations in this dataset in order to allow users to independently evaluate the quality of each individual SWOT measurement. As a result, the dataset may include observations flagged with varying quality levels, and the accuracy of individual SWOT water surface elevation values may vary depending on retrieval conditions, geolocation performance, surface roughness, layover effects, and other mission-related factors. The precision of SWOT data is dependent on the SWOT RiverSP and LakeSP data and values were not rounded here. Users should not interpret the accuracy of SWOT data based on the precision of data values. In situ gage stage measurements were obtained from the respective operating agencies, described in Processing Step 3. Gage stage measurements are generally expected to be accurate within approximately 0.01 feet or 0.2 percent of effective stage; however, actual accuracy may vary depending on agency standards, instrumentation, site conditions, and maintenance practices. No additional modifications were made to the reported stage values. Gage elevations converted from NAVD88 or CGVD2013 to EGM2008 may be subject to additional errors from converting vertical datums, with details in Processing Step 4. Pairing between SWOT water bodies and in situ gage sites as described in Processing Step 1 was assessed through manual geospatial inspection. Each candidate pairing was visually evaluated to confirm that the gage was located on the same lake or waterbody represented by the SWOT observation. Gages located on tributaries, hydraulically disconnected channels, or otherwise not representative of the primary SWOT-observed waterbody were removed from the dataset. This manual review step was performed to reduce spatial misalignment and ensure that paired observations correspond to the same hydrologic feature. No independent field validation or statistical accuracy assessment was performed as part of this data release. Users are encouraged to consider known mission uncertainties, gage agency accuracy standards, and site-specific conditions when interpreting paired water surface elevation differences. Data were verified for completeness and any duplicate values were removed; in some instances there is more than one gage station affiliated with a river reach or lake, and in those cases both gages are included with redundant SWOT information. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Within the paired river reach and node datasets, in situ and SWOT elevations are populated, however, other fields such as gage flow may not be populated, as river discharge data were not available at all sites. In rare instances, other SWOT variables such as river slope or river width may not be populated if insufficient SWOT data were available for that observation to resolve width and slope estimates. A formal accuracy assessment of the horizontal positional information in the data set has not been conducted; horizontal data are taken directly from gage site information or from SWOT coordinate data. Latitude and longitude coordinates associated with gage stations vary in precision based on the gage source data. A formal accuracy assessment of the vertical accuracy in the data set has not been conducted; elevation data are taken directly from stage information or from SWOT elevation data. SWOT elevation data are expected to vary in accuracy, whereas stage accuracy is estimated to be within ±0.01 feet or 0.2 percent of the effective stage. Gage elevations converted from NAVD88 or CGVD2013 to EGM2008 may be subject to additional errors from converting vertical datums. Surface Water Ocean Topography (SWOT) 20250428 Version D tabular digital data online PODAAC Surface Water Ocean Topography (SWOT). 2025. SWOT Level 2 Lake Single-Pass Vector Data Product, Version D. Ver. D. PO.DAAC, CA, USA. Dataset accessed 2026-01-01 at https://doi.org/10.5067/SWOT-LAKESP-D https://doi.org/10.5067/SWOT-LAKESP-D Digital and/or Hardcopy 20221216 20260101 observed SWOT LakeSP Version D SWOT lake data from Version D data were downloaded and paired with in situ gage observations for lakes coincident with a given monitoring gage in the United States and Canada. Surface Water Ocean Topography (SWOT) 20240306 Version C tabular digital data online PODAAC Surface Water Ocean Topography (SWOT). 2024. SWOT Level 2 Lake Single-Pass Vector Data Product, Version C. Ver. C. PO.DAAC, CA, USA. Dataset accessed 2026-01-01 at https://doi.org/10.5067/SWOT-LAKESP-2.0 https://doi.org/10.5067/SWOT-LAKESP-2.0 Digital and/or Hardcopy 20221216 20250202 observed SWOT LakeSP Version C SWOT lake data from Version C data were downloaded and paired with in situ gage observations for lakes coincident with a given monitoring gage in the United States and Canada. Surface Water Ocean Topography (SWOT) 20250428 Version D tabular digital data online PODAAC Surface Water Ocean Topography (SWOT). 2025. SWOT Level 2 River Single-Pass Vector Data Product, Version D. Ver. D. PO.DAAC, CA, USA. Dataset accessed 2026-01-01 at https://doi.org/10.5067/SWOT-RIVERSP-D https://doi.org/10.5067/SWOT-RIVERSP-D Digital and/or Hardcopy 20221216 20260101 observed SWOT RiverSP Version D SWOT river reach and river node data from Version D data were downloaded and paired with in situ gage observations for rivers coincident with a given monitoring gage in the United States and Canada. Surface Water Ocean Topography (SWOT) 20240306 Version C tabular digital data online PODAAC Surface Water Ocean Topography (SWOT). 2024. SWOT Level 2 River Single-Pass Vector Data Product, Version C. Ver. C. PO.DAAC, CA, USA. Dataset accessed 2026-01-01 at https://doi.org/10.5067/SWOT-RIVERSP-2.0 https://doi.org/10.5067/SWOT-RIVERSP-2.0 Digital and/or Hardcopy 20221216 20250202 observed SWOT RiverSP Version C SWOT river reach and river node data from Version C data were downloaded and paired with in situ gage observations for rivers coincident with a given monitoring gage in the United States and Canada. Step 1: Pairing SWOT and gage sites In situ gage locations from U.S. and Canadian agencies were spatially paired with SWOT-observable waterbodies. River gages were paired to SWOT reaches and nodes by buffering SWOT vector geometries by 1 kilometer and performing a spatial intersection with gage point locations. Lake gages were intersected directly with lake polygons from the SWOT vector product without buffering. All candidate pairings were manually inspected in a geographic information system to verify that gages were located on the same river reach or lake represented by the SWOT feature. Gages located on tributaries, distributaries, hydraulically disconnected channels, or otherwise not representative of the primary SWOT-observed waterbody were removed. This manual review step was performed to minimize spatial mismatch and ensure hydrologic consistency between paired features. 20260101 USGS - WATER Merritt E Harlan Mendenhall Researcher mailing and physical

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Lakewood CO 80225 (774)641-4099 mharlan@usgs.gov Step 2: Acquiring SWOT data SWOT water surface elevation (WSE) data were obtained directly from NASA Surface Water and Ocean Topography (SWOT) Level-2 Hydrology products. Data were downloaded in time series format using the publicly available Hydrocron application programming interface (API). No additional quality filtering was applied to the SWOT observations at the time of acquisition. All available WSE observations and associated quality flags were retained in order to allow users to independently assess data quality and apply filtering criteria appropriate for their analyses. 20260101 Step 3: Acquiring Gage Data United States gage stage and metadata were obtained from the U.S. Geological Survey National Water Information System (NWIS) using the dataRetrieval R package and the U.S. Bureau of Reclamation (BOR) database using the RISE API. Canadian gage data were obtained from Environment and Climate Change Canada (ECCC) using the tidyhydat R package and Québec’s Ministry of the Environment (CEHQ) using the web portal: https://www.cehq.gouv.qc.ca/atlas-hydroclimatique/stations-hydrometriques/index-en.htm. Time series data, site metadata, and datum information were retrieved using the aforementioned agency APIs and R packages designed for programmatic access. No additional quality assurance filtering was applied beyond that provided by the source agencies, with the exception of limited spot checks for anomalous values. Across those checks, no systematic data errors were identified. 20260101 Step 4: Converting Gage Datum To enable direct comparison with SWOT WSE products, gage stage measurements were converted to water surface elevations referenced to the EGM2008 geoid where possible, consistent with SWOT products. For U.S. gages referenced to NAD83/NAVD88, elevations were converted to EGM2008 using NOAA’s Vertical Datum Transformation Tool (VDatum). Transformations accounted for horizontal reference frames, vertical datum shifts, and epoch differences. Epoch conversions were performed using epoch 2010.0 for NAD83-referenced data and the epoch corresponding to the paired SWOT observation (rounded to the nearest 0.1 year). Because VDatum provides EGM2008 in a tide-free system and SWOT elevations are referenced to the mean-tide system, a latitude-dependent mean-tide correction was applied using the formulation provided in the SWOT User Handbook. Final in situ water surface elevations referenced to EGM2008 were computed by adding the local datum offset, the EGM2008 vertical transformation, and the mean-tide correction. For Canadian gages, vertical transformations were performed where sufficient datum information was available. Gages referenced to CGVD28 were first converted to CGVD2013, then transformed to ITRF2014/EGM2008 using the ECCC TRX tool. Mean-tide corrections were applied using the same latitude-based formulation described above. Gages lacking sufficient datum metadata were not vertically transformed and were excluded from same-datum conversions. 20260101 Step 5: Pairing SWOT and Gage Observations and Exporting Data SWOT WSE observations were temporally paired with in situ gage observations by selecting the nearest available 15-minute observation (or daily value, where applicable). Observation pairs were retained only if they fell within a ±1-hour time window. Records with missing values were excluded. Reach, node, and lake paired data were saved separately in csv files, and metadata site information was also extracted and saved across reach, node, and lake data. These outputs were then used to evaluate SWOT water surface elevation relative to in situ water surface elevation in a Pareto analysis described in Step 6. 20260101 Step 6: Filtering Analysis To evaluate how SWOT data quality metrics relate to observed water surface elevation differences between SWOT and in situ measurements, a grid search filtering analysis was conducted. Sequential filters based on SWOT-provided quality flags and related metrics were applied to the paired dataset. The percentage of retained observations and summary accuracy metrics were computed after each filter step. This analysis enables users to assess tradeoffs between data retention and data quality and to evaluate how combinations of quality criteria influence the distribution of SWOT–in situ water surface elevation differences. 20260101 1e-05 1e-05 Decimal degrees WGS84 WGS_1984 6378137.0 298.257 Earth Gravitational Model EGM2008 1e-02 meters Attribute values paired_lake_SWOT_sites.csv This dataset contains site-level information for lakes included in the SWOT in situ comparison dataset, including site identifiers, geographic coordinates, and associated metadata. It provides the reference site information only; corresponding files contain the paired SWOT and in situ water surface elevation data. Producer Defined gage_agency Abbreviated name of the organization providing gage data Producer Defined USGS U.S. Geological Survey Producer defined BOR U.S. Bureau of Reclamation Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 27.11850278 65.7787704467773 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -147.200797 -56.5764694213867 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency EGM96 Earth Gravitational Model from 1996 Gage agency OTHER Other datum or local reference Gage agency USGS 1912 1912 (4th General) adjustment of the United States level net Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency FRENCH RIVER DATUM CHS Chart 6036, part of nautical charts Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency SERVICE GEODESIQUE DU CANADA (ANCIEN DATUM) Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency NEWFOUNDLAND HYDRO DATUM Newfoundland hydro datum, some of which are referenced to CGVD2013 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency GEODETIC SURVEY OF CANADA DATUM Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency PRAIRIE FARM REHABILITATION ADMINISTRATION DATUM PRFA datum based on a program headquartered in Saskatchewan. Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1963 ADJ.) Geodetic Survey of Canada Datum adjusted in 1963 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ALBERTA DEPARTMENT OF HIGHWAYS DATUM Alberta Department of Highways local vertical datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1961 ADJ.) Geodetic Survey of Canada Datum adjusted in 1961 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1980 ADJ.) Geodetic Survey of Canada Datum adjusted in 1980 Gage agency TOPOGRAPHIC SURVEY DATUM Topographic survey datum Gage agency lake_id Lake identification number from the SWOT Prior Lake Database SWOT_L2_HR_LakeSP 7110012843 8520534092 p_ref_area Reference water surface area used to compute the storage change SWOT_L2_HR_LakeSP 0.0126 82218.201222 square kilometers PLD_version Version of the Prior Lake Database for the associated lake_id SWOT_L2_HR_LakeSP 105 Prior Lake Database version 105 Producer defined 106 Prior Lake Database version 106 Producer defined 202 Prior Lake Database version 202 Producer defined SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_reach_SWOT_sites.csv This dataset contains site-level information for river reaches included in the SWOT in situ comparison dataset, including site identifiers, geographic coordinates, and associated metadata. It provides the reference site information only; corresponding files contain the paired SWOT and in situ water surface elevation data. Producer Defined gage_agency Abbreviated name of the organization providing gage data Producer Defined USGS U.S. Geological Survey Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 28.08473879 70.2813799 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -163.677559 -53.5686111450195 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency COE1912 1912 (4th General) adjustment of the United States level net Gage agency IGLD International Great Lakes Datum Gage agency GEODETIC SURVEY OF CANADA DATUM Canadian Geodetic Datum of 1928- CGVD28 Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH2010 Canadian Geodetic Datum of 1928- CGVD28 Gage agency SERVICE GEODESIQUE DU CANADA Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency INTERNATIONAL DES GRANDS LACS (1955) International Great Lakes Datum (IGLD) of 1955 Gage agency GEODESIQUES Geodetic datum Gage agency SERVICE GEODESIQUE DU CANADA (AJUST. LOCAL 1969) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1929 ADJ.) Geodetic Survey of Canada Datum adjusted in 1929 Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH1997 Canadian Geodetic Datum of 1928- CGVD28 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1985 ADJ.) Geodetic Survey of Canada Datum adjusted in 1985 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1954 ADJ.) Geodetic Survey of Canada Datum adjusted in 1985 Gage agency SAND HEADS DATUM National Geodetic Vertical Datum of 1929 mean sea level datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1951 ADJ.) Geodetic Survey of Canada Datum adjusted in 1954 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1983 ADJ.) Geodetic Survey of Canada Datum adjusted in 1983 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1982 ADJ.) Geodetic Survey of Canada Datum adjusted in 1982 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1987 ADJ.) Geodetic Survey of Canada Datum adjusted in 1987 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1992 ADJ.) Geodetic Survey of Canada Datum adjusted in 1992 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1984 ADJ.) Geodetic Survey of Canada Datum adjusted in 1984 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1991 ADJ.) Geodetic Survey of Canada Datum adjusted in 1991 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1988 ADJ.) Geodetic Survey of Canada Datum adjusted in 1988 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1981 ADJ.) Geodetic Survey of Canada Datum adjusted in 1981 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1976 ADJ.) Geodetic Survey of Canada Datum adjusted in 1976 Gage agency reach_id Unique reach identifier from the Prior River Database SWOT_L2_HR_RiverSP 71140100161 83245000583 p_length Length of the river reach or node SWOT_L2_HR_RiverSP 757.674056 19996.385158 meters p_width River width from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 11.0 3348.0 meters p_wse River water surface elevation, relative to the geoid, from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 0.0 2390.5 meters sword_version Version of the Prior River Database for the associated river identification SWOT_L2_HR_RiverSP 16 Prior River Database version 16, affiliated with SWOT Version C data SWOT_L2_HR_RiverSP 7b Prior River Database version 17b, affiliated with SWOT Version D data SWOT_L2_HR_RiverSP SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_node_SWOT_sites.csv This dataset contains site-level information for river nodes included in the SWOT in situ comparison dataset, including site identifiers, geographic coordinates, and associated metadata. It provides the reference site information only; corresponding files contain the paired SWOT and in situ water surface elevation data. Producer Defined gage_agency Abbreviated name of the organization providing gage data Producer Defined USGS U.S. Geological Survey Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 28.08473879 70.2813799 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -163.677559 -53.5686111450195 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency COE1912 1912 (4th General) adjustment of the United States level net Gage agency IGLD International Great Lakes Datum Gage agency GEODETIC SURVEY OF CANADA DATUM Canadian Geodetic Datum of 1928- CGVD28 Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH2010 Canadian Geodetic Datum of 1928- CGVD28 Gage agency SERVICE GEODESIQUE DU CANADA Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency INTERNATIONAL DES GRANDS LACS (1955) International Great Lakes Datum (IGLD) of 1955 Gage agency GEODESIQUES Geodetic datum Gage agency SERVICE GEODESIQUE DU CANADA (AJUST. LOCAL 1969) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1929 ADJ.) Geodetic Survey of Canada Datum adjusted in 1929 Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH1997 Canadian Geodetic Datum of 1928- CGVD28 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1985 ADJ.) Geodetic Survey of Canada Datum adjusted in 1985 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1954 ADJ.) Geodetic Survey of Canada Datum adjusted in 1954 Gage agency SAND HEADS DATUM National Geodetic Vertical Datum of 1929 mean sea level datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1951 ADJ.) Geodetic Survey of Canada Datum adjusted in 1951 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1983 ADJ.) Geodetic Survey of Canada Datum adjusted in 1983 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1982 ADJ.) Geodetic Survey of Canada Datum adjusted in 1982 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1987 ADJ.) Geodetic Survey of Canada Datum adjusted in 1987 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1992 ADJ.) Geodetic Survey of Canada Datum adjusted in 1992 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1984 ADJ.) Geodetic Survey of Canada Datum adjusted in 1984 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1991 ADJ.) Geodetic Survey of Canada Datum adjusted in 1991 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1988 ADJ.) Geodetic Survey of Canada Datum adjusted in 1988 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1981 ADJ.) Geodetic Survey of Canada Datum adjusted in 1981 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1976 ADJ.) Geodetic Survey of Canada Datum adjusted in 1976 Gage agency node_id Unique node identifier from the Prior River Database SWOT_L2_HR_RiverSP 71140100160351 83245000580203 p_dam_id Dam ID from the Global Reservoir and Dam (GRanD) database SWOT_L2_HR_RiverSP 0 25354 p_width River width from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 11.0 4878.5 meters p_wse River water surface elevation, relative to the geoid, from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 0.0 2385.6001 meters sword_version Version of the Prior River Database for the associated river identification SWOT_L2_HR_RiverSP 16 Prior River Database version 16, affiliated with SWOT Version C data SWOT_L2_HR_RiverSP 7b Prior River Database version 17b, affiliated with SWOT Version D data SWOT_L2_HR_RiverSP SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_lake_SWOT_gage.csv This dataset contain paired Surface Water and Ocean Topography (SWOT) satellite–derived water surface elevation observations and corresponding in situ gage measurements for the listed lake sites, including associated timestamps and SWOT measurements and flags. Producer Defined gage_agency Abbreviated name of the organization providing gage data Producer Defined USGS U.S. Geological Survey Producer defined BOR U.S. Bureau of Reclamation Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 27.11850278 65.7787704467773 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -147.200797 -56.5764694213867 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency EGM96 Earth Gravitational Model from 1996 Gage agency OTHER Other datum or local reference Gage agency USGS 1912 1912 (4th General) adjustment of the United States level net Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency FRENCH RIVER DATUM CHS Chart 6036, part of nautical charts Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency SERVICE GEODESIQUE DU CANADA (ANCIEN DATUM) Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency NEWFOUNDLAND HYDRO DATUM Newfoundland hydro datum, some of which are referenced to CGVD2013 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency GEODETIC SURVEY OF CANADA DATUM Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency PRAIRIE FARM REHABILITATION ADMINISTRATION DATUM PRFA datum based on a program headquartered in Saskatchewan. Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1963 ADJ.) Geodetic Survey of Canada Datum adjusted in 1963 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ALBERTA DEPARTMENT OF HIGHWAYS DATUM Alberta Department of Highways local vertical datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1961 ADJ.) Geodetic Survey of Canada Datum adjusted in 1961 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1980 ADJ.) Geodetic Survey of Canada Datum adjusted in 1980 Gage agency TOPOGRAPHIC SURVEY DATUM Topographic survey datum Gage agency gage_time_UTC Date and time of the paired gage observation in Coordinated Universal Time Gage agency 2023-03-29T05:30:00Z 2026-01-01T07:00:00Z datetime in Coordinated Universal Time gage_stage_m Water level or stage from the gage station measured with an in situ sensor Gage agency -2.036 3052.755 meters gage_wse_EGM2008 Water surface elevation from the gage station converted to EGM2008 vertical datum to directly compare with SWOT water surface elevations Producer Defined NA Water surface elevation data were not converted to EGM2008 Producer defined -1.141 3052.237 meters lake_id Lake identification number from the SWOT Prior Lake Database SWOT_L2_HR_LakeSP 7110012843 8520534092 SWOT_time Date and time of the paired SWOT observation in Coordinated Universal Time SWOT_L2_HR_LakeSP 2023-03-29T05:29:43Z 2025-12-31T19:04:31Z datetime in Coordinated Universal Time SWOT_latitude Latitude coordinate of the SWOT observation in decimal degrees SWOT_L2_HR_LakeSP 27.124444 65.52322 decimal degrees SWOT_longitude Longitude coordinate of the SWOT observation in decimal degrees SWOT_L2_HR_LakeSP -147.209409 -56.596404 decimal degrees wse Water surface elevation from the SWOT observation SWOT_L2_HR_LakeSP -154.298 3357.265 meters wse_u Total uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_LakeSP << empty cell >> No water surface elevation uncertainty estimate was provided Producer defined 0.0 84.594 meters wse_r_u Random-only component of the uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_LakeSP 0.0 10.15 meters wse_std Standard deviation of the SWOT water surface elevation of all the pixels composing the lake SWOT_L2_HR_LakeSP 0.0 872.38 meters area_total Total estimated SWOT water surface area SWOT_L2_HR_LakeSP 0.010533 37401.046969 square kilometers area_tot_u Total uncertainty in the total estimated water surface area SWOT_L2_HR_LakeSP 0.000253 30.179921 square kilometers area_detct Actual SWOT-detected water surface area, including open water and water near land SWOT_L2_HR_LakeSP 0.0035 37320.15 square kilometers area_det_u Total uncertainty in the surface area of the detected water pixels SWOT_L2_HR_LakeSP 0.000253 30.179921 square kilometers quality_f Summary quality indicator for the SWOT measurement SWOT_L2_HR_LakeSP 0 good measurement SWOT_L2_HR_LakeSP 1 suspect measurement that may have large errors SWOT_L2_HR_LakeSP 2 degraded measurement that likely has large errors SWOT_L2_HR_LakeSP 3 bad measurement that may be nonsensical and should be ignored SWOT_L2_HR_LakeSP dark_frac Fraction of the node total area covered by dark water, equal to 1-(area_detct/area_total) SWOT_L2_HR_LakeSP << empty cell >> No dark fraction estimate was provided Producer defined 0.0 0.999916 ice_clim_f Climatological ice cover flag indicating whether the lake is ice-covered on the day of the observation based on climatological ice coverage SWOT_L2_HR_LakeSP -999 No ice climatological data are available for a given lake SWOT_L2_HR_LakeSP 0 likely not ice covered SWOT_L2_HR_LakeSP 1 may or may not be partially or fully ice covered SWOT_L2_HR_LakeSP 2 likely fully ice covered SWOT_L2_HR_LakeSP partial_f Partial SWOT observation coverage flag SWOT_L2_HR_LakeSP 0 observed lake is fully covered by a half-swath SWOT_L2_HR_LakeSP 1 observed lake hits the near- or far-range edge of the half-swath and may not be fully observed SWOT_L2_HR_LakeSP xovr_cal_q Flag that indicates the quality of the cross-over calibration SWOT_L2_HR_LakeSP 0 good quality cross-over calibration SWOT_L2_HR_LakeSP 1 suspect quality cross-over calibration SWOT_L2_HR_LakeSP 2 bad quality (missing) cross-over calibration SWOT_L2_HR_LakeSP p_ref_wse Reference water surface elevation used to the compute the storage change SWOT_L2_HR_LakeSP << empty cell >> No reference water surface elevation was provided Producer defined -0.098 3050.627 meters p_ref_area Reference water surface area used to compute the storage change SWOT_L2_HR_LakeSP 0.0126 82218.201222 square kilometers xtrk_dist Distance of the lake polygon centroid from the spacecraft nadir track SWOT_L2_HR_LakeSP -60782.117 59975.28 meters PLD_version Version of the Prior Lake Database for the associated lake_id SWOT_L2_HR_LakeSP 105 Prior Lake Database version 105 SWOT_L2_HR_LakeSP 106 Prior Lake Database version 106 SWOT_L2_HR_LakeSP 202 Prior Lake Database version 202 SWOT_L2_HR_LakeSP collection_shortname Name of the SWOT collection indicating data source and version SWOT_L2_HR_LakeSP SWOT_L2_HR_LakeSP_2.0 The collection corresponding to Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. SWOT_L2_HR_LakeSP SWOT_L2_HR_LakeSP_D The collection corresponding to the Version D products which resolves several known issues in the Version C science data products, and is available from 2023-03-30 until present. SWOT_L2_HR_LakeSP cycle_id Cycle number of the product SWOT_L2_HR_LakeSP 1 578 pass_id Pass number of the product SWOT_L2_HR_LakeSP 7 580 crid Composite release identifier (CRID) of the data system used to generate this file SWOT_L2_HR_LakeSP PGC0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency reprocessed products, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-03-30 through 2024-01-25. SWOT_L2_HR_LakeSP PIC0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-11-22 through 2024-10-15. SWOT_L2_HR_LakeSP PIC2 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 2 indicating updates from the previous version C data. These data are available from 2024-10-15 through 2025-05-03. Producer defined PGD0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-07-26 through 2025-02-02, with reprocessing in progress. SWOT_L2_HR_LakeSP PID0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2025-05-05 through 2026-01-01 (the latest date data were queried, data are still in production). SWOT_L2_HR_LakeSP SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_node_SWOT_gage.csv This dataset contain paired Surface Water and Ocean Topography (SWOT) satellite–derived water surface elevation observations and corresponding in situ gage measurements for the listed river node sites, including associated timestamps and SWOT measurements and flags. Producer Defined gage_agency Abbreviated name of the organization providing gage data Gage agency USGS U.S. Geological Survey Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 28.08473879 70.2813799 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -163.677559 -53.5686111450195 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency COE1912 1912 (4th General) adjustment of the United States level net Gage agency IGLD International Great Lakes Datum Gage agency GEODETIC SURVEY OF CANADA DATUM Canadian Geodetic Datum of 1928- CGVD28 Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH2010 Canadian Geodetic Datum of 1928- CGVD28 Gage agency SERVICE GEODESIQUE DU CANADA Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency INTERNATIONAL DES GRANDS LACS (1955) International Great Lakes Datum (IGLD) of 1955 Gage agency GEODESIQUES Geodetic datum Gage agency SERVICE GEODESIQUE DU CANADA (AJUST. LOCAL 1969) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1929 ADJ.) Geodetic Survey of Canada Datum adjusted in 1929 Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH1997 Canadian Geodetic Datum of 1928- CGVD28 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1985 ADJ.) Geodetic Survey of Canada Datum adjusted in 1985 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1954 ADJ.) Geodetic Survey of Canada Datum adjusted in 1954 Gage agency SAND HEADS DATUM National Geodetic Vertical Datum of 1929 mean sea level datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1951 ADJ.) Geodetic Survey of Canada Datum adjusted in 1951 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1983 ADJ.) Geodetic Survey of Canada Datum adjusted in 1983 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1982 ADJ.) Geodetic Survey of Canada Datum adjusted in 1982 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1987 ADJ.) Geodetic Survey of Canada Datum adjusted in 1987 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1992 ADJ.) Geodetic Survey of Canada Datum adjusted in 1992 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1984 ADJ.) Geodetic Survey of Canada Datum adjusted in 1984 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1991 ADJ.) Geodetic Survey of Canada Datum adjusted in 1991 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1988 ADJ.) Geodetic Survey of Canada Datum adjusted in 1988 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1981 ADJ.) Geodetic Survey of Canada Datum adjusted in 1981 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1976 ADJ.) Geodetic Survey of Canada Datum adjusted in 1976 Gage agency gage_time_UTC Date and time of the paired gage observation in Coordinated Universal Time Gage agency 2023-03-29T05:30:00Z 2025-12-31T20:50:00Z datetime in Coordinated Universal Time gage_stage_m Water level or stage from the gage station measured with an in situ sensor Gage agency -3.993 1094.141 meters gage_wse_EGM2008 Water surface elevation from the gage station converted to EGM2008 vertical datum to directly compare with SWOT water surface elevations Producer Defined NA Water surface elevation data were not converted to EGM2008 Producer defined -1.941 2384.641 meters gage_flow_m3s Streamflow recorded from the gage monitoring site at the closest 15-minute interval (daily for Quebec data) if available. Gage agency NA No streamflow data were available Producer defined -28316.77 37944.51 cubic meters per second node_id Unique node identifier from the Prior River Database SWOT_L2_HR_RiverSP 71140100160351 83245000580203 SWOT_time Date and time of the paired SWOT observation in Coordinated Universal Time SWOT_L2_HR_RiverSP 2023-03-29T05:28:32Z 2025-12-31T20:51:43Z datetime in Coordinated Universal Time SWOT_latitude Latitude coordinate of the SWOT observation in decimal degrees SWOT_L2_HR_RiverSP 28.0820593 70.28520655 decimal degrees SWOT_longitude Longitude coordinate of the SWOT observation in decimal degrees SWOT_L2_HR_RiverSP -163.6810883 -53.5659036 decimal degrees wse Water surface elevation from the SWOT observation SWOT_L2_HR_RiverSP -66.45519 2509.38867 meters wse_u Total uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_RiverSP 0.09 41.53831 meters wse_r_u Random-only component of the uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_RiverSP 1e-05 41.53822 meters width SWOT river width SWOT_L2_HR_RiverSP << empty cell >> No river width measurement was provided Producer defined -3.05945 192358.136796 meters width_u Total uncertainty in the SWOT-measured river width SWOT_L2_HR_RiverSP << empty cell >> No width uncertainty estimate was provided Producer defined 0.001315 34243746.8326 meters area_total Total estimated SWOT water surface area SWOT_L2_HR_RiverSP << empty cell >> No area estimate was provided Producer defined -486.5 35195881.1 square kilometers area_tot_u Total uncertainty in the total estimated water surface area SWOT_L2_HR_RiverSP << empty cell >> No area uncertainty estimate was provided Producer defined 0.3 6265598444.9 square kilometers area_detct Actual SWOT-detected water surface area, including open water and water near land SWOT_L2_HR_RiverSP << empty cell >> No area detected measurement was provided Producer defined -486.5 35195881.1 square kilometers area_det_u Total uncertainty in the surface area of the detected water pixels SWOT_L2_HR_RiverSP << empty cell >> No area detected uncertainty estimate was provided Producer defined 0.3 6265598444.9 square kilometers area_wse Area used to compute the water surface elevation SWOT_L2_HR_RiverSP << empty cell >> No area used to compute water surface elevation was provided Producer defined -49034.7 35195881.1 square meters node_q Summary quality indicator for the node measurement SWOT_L2_HR_RiverSP 0 good measurement SWOT_L2_HR_RiverSP 1 suspect measurement that may have large errors SWOT_L2_HR_RiverSP 2 degraded measurement that likely has large errors SWOT_L2_HR_RiverSP 3 bad measurement that may be nonsensical and should be ignored SWOT_L2_HR_RiverSP node_q_b Bitwise quality indicator for the node measurement SWOT_L2_HR_RiverSP 0 13389315 dark_frac Fraction of the node total area covered by dark water, equal to 1-(area_detct/area_total) SWOT_L2_HR_RiverSP << empty cell >> No dark fraction estimate was provided Producer defined 0.0 1.0 ice_clim_f Climatological ice cover flag indicating whether the lake is ice-covered on the day of the observation based on climatological ice coverage SWOT_L2_HR_RiverSP -999 No ice climatological data are available for a given lake SWOT_L2_HR_RiverSP 0 likely not ice covered SWOT_L2_HR_RiverSP 1 may or may not be partially or fully ice covered SWOT_L2_HR_RiverSP 2 likely fully ice covered SWOT_L2_HR_RiverSP n_good_pix Number of good pixels that have a valid water surface elevation SWOT_L2_HR_RiverSP 0 2 xovr_cal_q Flag that indicates the quality of the cross-over calibration SWOT_L2_HR_RiverSP 0 good quality cross-over calibration SWOT_L2_HR_RiverSP 1 suspect quality cross-over calibration SWOT_L2_HR_RiverSP 2 bad quality (missing) cross-over calibration SWOT_L2_HR_RiverSP p_length Length of the river node SWOT_L2_HR_RiverSP 100.00136439 307.9418039 meters p_width River width from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 11.0 4878.5 meters p_wse River water surface elevation, relative to the geoid, from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 0.0 2385.6001 meters p_n_ch_mod Maximum number of channels detected in the river SWOT_L2_HR_RiverSP 1 3 p_dam_id Dam ID from the Global Reservoir and Dam (GRanD) database SWOT_L2_HR_RiverSP 0 The waterbody is not within the Global Reservoir and Dam database Producer defined 272 25354 xtrk_dist Distance of the node centroid from the spacecraft nadir track SWOT_L2_HR_RiverSP << empty cell >> No cross track distance was provided Producer defined -69025.14062 74823.64062 meters sword_version Version of the Prior River Database for the associated river identification SWOT_L2_HR_RiverSP 16 Prior River Database version 16, affiliated with SWOT Version C data SWOT_L2_HR_RiverSP 7b Prior River Database version 17b, affiliated with SWOT Version D data SWOT_L2_HR_RiverSP collection_shortname Name of the SWOT collection indicating data source and version SWOT_L2_HR_RiverSP SWOT_L2_HR_RiverSP_2.0 The collection corresponding to Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. SWOT_L2_HR_RiverSP SWOT_L2_HR_RiverSP_D The collection corresponding to the Version D products which resolves several known issues in the Version C science data products, and is available from 2023-03-30 until present. SWOT_L2_HR_RiverSP cycle_id Cycle number of the product SWOT_L2_HR_RiverSP 1 578 pass_id Pass number of the product SWOT_L2_HR_RiverSP 7 582 crid Composite release identifier (CRID) of the data system used to generate this file SWOT_L2_HR_RiverSP PGC0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency reprocessed products, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-03-30 through 2024-01-25. SWOT_L2_HR_RiverSP PIC0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-11-22 through 2024-10-15. SWOT_L2_HR_RiverSP PIC2 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 2 indicating updates from the previous version C data. These data are available from 2024-10-15 through 2025-05-03. SWOT_L2_HR_RiverSP PGD0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-07-26 through 2025-02-02, with reprocessing in progress. SWOT_L2_HR_RiverSP PID0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2025-05-05 through 2026-01-01 (the latest date data were queried, data are still in production). SWOT_L2_HR_RiverSP SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_reach_SWOT_gage.csv This dataset contain paired Surface Water and Ocean Topography (SWOT) satellite–derived water surface elevation observations and corresponding in situ gage measurements for the listed river reach sites, including associated timestamps and SWOT measurements and flags. Producer Defined gage_agency Abbreviated name of the organization providing gage data Producer Defined USGS U.S. Geological Survey Producer defined ECCC Environment and Climate Change Canada Producer defined Quebec Quebec Ministry of the Environment Producer defined gage_id Gage monitoring station identification value Gage agency Unique identifier of the gage monitoring station gage_name Name of the gage station Gage agency Unique name of the gage monitoring station gage_latitude Latitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency 28.08473879 70.2813799 decimal degrees gage_longitude Longitude coordinate of the gage station in decimal degrees. Precision may vary based on source data. Gage agency -163.677559 -53.5686111450195 decimal degrees gage_coord_datum Horizontal datum associated with the latitude and longitude coordinates for the gage stations Gage agency NAD83 North American Datum of 1983 Gage agency WGS84 World Geodetic System 1984 Gage agency gage_alt_datum Vertical datum associated with the gage stage measurements if applicable Gage agency << empty cell >> No vertical datum provided or found Producer defined NAVD88 North American Vertical Datum of 1988 Gage agency NGVD29 National Geodetic Vertical Datum of 1929 Gage agency COE1912 1912 (4th General) adjustment of the United States level net Gage agency IGLD International Great Lakes Datum Gage agency GEODETIC SURVEY OF CANADA DATUM Canadian Geodetic Datum of 1928- CGVD28 Gage agency CANADIAN GEODETIC VERTICAL DATUM 2013:EPOCH2010 Canadian Geodetic Vertical Datum of 2013-CGVD2013 Gage agency ASSUMED DATUM NO. 2 Arbitrary or assumed local coordinate system Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH2010 Canadian Geodetic Datum of 1928- CGVD28 Gage agency SERVICE GEODESIQUE DU CANADA Geodetic Service of Canada Reference System, either CGVD28 or CGVD2013 Gage agency INTERNATIONAL DES GRANDS LACS (1955) International Great Lakes Datum (IGLD) of 1955 Gage agency GEODESIQUES Geodetic datum Gage agency SERVICE GEODESIQUE DU CANADA (AJUST. LOCAL 1969) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency ASSUMED DATUM Arbitrary or assumed local coordinate system Gage agency APPROXIMATE GEODETIC SURVEY OF CANADA DATUM Approximate Canadian Geodetic Survey, either CGVD28 or CGVD2013 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1929 ADJ.) Geodetic Survey of Canada Datum adjusted in 1929 Gage agency CANADIAN GEODETIC VERTICAL DATUM 1928:EPOCH1997 Canadian Geodetic Datum of 1928- CGVD28 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1969 ADJ.) Geodetic Survey of Canada Datum adjusted in 1969 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1985 ADJ.) Geodetic Survey of Canada Datum adjusted in 1985 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1954 ADJ.) Geodetic Survey of Canada Datum adjusted in 1954 Gage agency SAND HEADS DATUM National Geodetic Vertical Datum of 1929 mean sea level datum Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1951 ADJ.) Geodetic Survey of Canada Datum adjusted in 1951 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1983 ADJ.) Geodetic Survey of Canada Datum adjusted in 1983 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1982 ADJ.) Geodetic Survey of Canada Datum adjusted in 1982 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1987 ADJ.) Geodetic Survey of Canada Datum adjusted in 1987 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1992 ADJ.) Geodetic Survey of Canada Datum adjusted in 1992 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1984 ADJ.) Geodetic Survey of Canada Datum adjusted in 1984 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1991 ADJ.) Geodetic Survey of Canada Datum adjusted in 1991 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1988 ADJ.) Geodetic Survey of Canada Datum adjusted in 1988 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1981 ADJ.) Geodetic Survey of Canada Datum adjusted in 1981 Gage agency GEODETIC SURVEY OF CANADA DATUM (LOCAL 1976 ADJ.) Geodetic Survey of Canada Datum adjusted in 1976 Gage agency gage_time_UTC Date and time of the paired gage observation in Coordinated Universal Time Gage agency 2023-03-29T05:30:00Z 2025-12-31T20:50:00Z datetime in Coordinated Universal Time gage_stage_m Water level or stage from the gage station measured with an in situ sensor Gage agency -3.993 1094.141 meters gage_flow_m3s Streamflow recorded from the gage monitoring site at the closest 15-minute interval (daily for Quebec data) if available. Gage agency NA No streamflow data were available Producer defined -28316.77 37944.51 cubic meters per second reach_id Unique reach identifier from the Prior River Database SWOT_L2_HR_RiverSP 71140100161 83245000583 SWOT_time Date and time of the paired SWOT observation in Coordinated Universal Time SWOT_L2_HR_RiverSP 2023-03-29T05:28:32Z 2025-12-31T20:51:43Z datetime in Coordinated Universal Time wse Water surface elevation from the SWOT observation SWOT_L2_HR_RiverSP -183.6901 2732.0958 meters wse_u Total uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_RiverSP 0.09001 302.31865 meters wse_r_u Random-only component of the uncertainty in the SWOT water surface elevation observation SWOT_L2_HR_RiverSP 0.0012 302.31863 meters slope Water surface slope with respect to the geoid SWOT_L2_HR_RiverSP << empty cell >> No slope measurement was available Producer defined -0.4384487605 0.14020524247 meters per meter slope_u Total uncertainty of the water surface slope SWOT_L2_HR_RiverSP << empty cell >> No slope uncertainty estimate was available Producer defined 3.12284e-06 0.00144746344 meters per meter slope_r_u Random uncertainty of the water surface slope SWOT_L2_HR_RiverSP << empty cell >> No random slope uncertainty estimate was provided Producer defined 8.6728e-07 0.00144746033 meters per meter slope2 Enhanced water surface slope with respect to the geoid SWOT_L2_HR_RiverSP << empty cell >> No enhanced slope measurement was provided Producer defined -0.4832459009 0.10825225334 meters per meter width SWOT river width SWOT_L2_HR_RiverSP << empty cell >> No river width measurement was provided Producer defined 0.0 37685.917176 meters width_u Total uncertainty in the SWOT-measured river width SWOT_L2_HR_RiverSP << empty cell >> No width uncertainty estimate was provided Producer defined 0.0 134515704.926 meters area_total Total estimated SWOT water surface area SWOT_L2_HR_RiverSP << empty cell >> No area measurement was provided Producer defined 0.0 484560828.7 square kilometers area_tot_u Total uncertainty in the total estimated water surface area SWOT_L2_HR_RiverSP << empty cell >> No area uncertainty estimate was provided Producer defined 0.0 999999999999.0 square kilometers area_detct Actual SWOT-detected water surface area, including open water and water near land SWOT_L2_HR_RiverSP << empty cell >> No area detected measurement was provided Producer defined 0.0 484405039.9 square kilometers area_det_u Total uncertainty in the surface area of the detected water pixels SWOT_L2_HR_RiverSP << empty cell >> No area detected uncertainty estimate was provided Producer defined 0.0 999999999999.0 square kilometers area_wse Area used to compute the water surface elevation SWOT_L2_HR_RiverSP << empty cell >> No area water surface elevation was provided Producer defined 58.1 327988177.0 square meters reach_q Summary quality indicator for the node measurement SWOT_L2_HR_RiverSP 0 good measurement SWOT_L2_HR_RiverSP 1 suspect measurement that may have large errors SWOT_L2_HR_RiverSP 2 degraded measurement that likely has large errors SWOT_L2_HR_RiverSP 3 bad measurement that may be nonsensical and should be ignored SWOT_L2_HR_RiverSP reach_q_b Bitwise quality indicator for the node measurement SWOT_L2_HR_RiverSP 0 71335936 dark_frac Fraction of the reach total area covered by dark water, equal to 1-(area_detct/area_total) SWOT_L2_HR_RiverSP 0.0 0.99938350056 ice_clim_f Climatological ice cover flag indicating whether the lake is ice-covered on the day of the observation based on climatological ice coverage SWOT_L2_HR_RiverSP -999 No ice climatological data are available for a given lake SWOT_L2_HR_RiverSP 0 likely not ice covered SWOT_L2_HR_RiverSP 1 may or may not be partially or fully ice covered SWOT_L2_HR_RiverSP 2 likely fully ice covered SWOT_L2_HR_RiverSP partial_f Partial SWOT observation coverage flag SWOT_L2_HR_RiverSP 0 observed lake is fully covered by a half-swath SWOT_L2_HR_RiverSP 1 observed lake hits the near- or far-range edge of the half-swath and may not be fully observed SWOT_L2_HR_RiverSP n_good_nod Number of nodes in the reach that have a valid water surface elevation SWOT_L2_HR_RiverSP 2 100 xovr_cal_q Flag that indicates the quality of the cross-over calibration SWOT_L2_HR_RiverSP 0 good quality cross-over calibration SWOT_L2_HR_RiverSP 1 suspect quality cross-over calibration SWOT_L2_HR_RiverSP 2 bad quality (missing) cross-over calibration SWOT_L2_HR_RiverSP p_length Length of the river reach SWOT_L2_HR_RiverSP 757.674056 19996.385158 meters p_width River width from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 11.0 3348.0 meters p_wse River water surface elevation, relative to the geoid, from the Prior River Database, also known as the SWOT River Database (SWORD) SWOT_L2_HR_RiverSP 0.0 2390.5 meters p_n_ch_mod Maximum number of channels detected in the river SWOT_L2_HR_RiverSP 1 3 p_dam_id Dam ID from the Global Reservoir and Dam (GRanD) database SWOT_L2_HR_RiverSP 0 The waterbody is not within the Global Reservoir and Dam database Producer defined 272 23327 p_n_nodes Number of nodes in the reach SWOT_L2_HR_RiverSP 4 100 p_low_slp Low slope flag from the Prior River Database SWOT_L2_HR_RiverSP 0 0 xtrk_dist Distance of the reach centroid from the spacecraft nadir track SWOT_L2_HR_RiverSP << empty cell >> No cross track distance was provided Producer defined -67965.60156 72201.13281 meters sword_version Version of the Prior River Database for the associated river identification SWOT_L2_HR_RiverSP 16 Prior River Database version 16, affiliated with SWOT Version C data SWOT_L2_HR_RiverSP 7b Prior River Database version 17b, affiliated with SWOT Version D data SWOT_L2_HR_RiverSP collection_shortname Name of the SWOT collection indicating data source and version SWOT_L2_HR_RiverSP SWOT_L2_HR_RiverSP_2.0 The collection corresponding to Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. SWOT_L2_HR_RiverSP SWOT_L2_HR_RiverSP_D The collection corresponding to the Version D products which resolves several known issues in the Version C science data products, and is available from 2023-03-30 until present. SWOT_L2_HR_RiverSP cycle_id Cycle number of the product SWOT_L2_HR_RiverSP 1 578 pass_id Pass number of the product SWOT_L2_HR_RiverSP 7 582 crid Composite release identifier (CRID) of the data system used to generate this file SWOT_L2_HR_RiverSP PGC0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency reprocessed products, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-03-30 through 2024-01-25. SWOT_L2_HR_RiverSP PIC0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-11-22 through 2024-10-15. SWOT_L2_HR_RiverSP PIC2 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, C indicating the major release version, and 2 indicating updates from the previous version C data. These data are available from 2024-10-15 through 2025-05-03. SWOT_L2_HR_RiverSP PGD0 SWOT data processed under routine operational environment (P), with G indicating the highest fidelity and longest latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2023-07-26 through 2025-02-02, with reprocessing in progress. SWOT_L2_HR_RiverSP PID0 SWOT data processed under routine operational environment (P), with I indicating medium fidelity and shorter latency, D indicating the major release version, and 0 indicating the first minor version. These data are available from 2025-05-05 through 2026-01-01 (the latest date data were queried, data are still in production). SWOT_L2_HR_RiverSP SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined paired_filtering_analysis.csv A grid-search of possible SWOT data quality filters and remaining data percentage and accuracy from the paired measurements across all reach, node, and lake data. Producer Defined wse_pdiff Maximum allowed threshold for the water surface elevation prior difference, or the absolute value of the difference between the SWOT-observed water surface elevation, and the Prior River Database water surface elevation. In this case, 10 meters is the strictest threshold, with no bound or infinity as the most relaxed filter. Producer Defined 10.0 inf dark_frac Maximum allowed dark water fraction, or the fraction of the total SWOT measurement area covered by dark water, equal to 1-(area_detct/area_total). Producer Defined 0.25 inf outlier_flag A flag indicating whether the SWOT observation is an outlier as identified by a Hampel outlier filter. An outlier is identified from a moving window, flagging observations that fall outside the range from a three-point moving median by more than three times the median absolute deviation (MAD), following the formulation in Equation 1 from Pearson et al. (2016): median[t] ^2±h*(1.4826*MAD[t]) where h = 3 and t represents a given SWOT water surface elevation observation. Producer Defined 0 The SWOT water surface elevation observation is NOT identified as an outlier Producer defined 1 The SWOT water surface elevation observation IS identified as an outlier Producer defined ice_clim_f Threshold allowed for the ice climatology flag indicating whether the SWOT observation is ice-covered on the day of the observation based on climatological ice coverage. Producer Defined 0 Only likely ice-free measurements (or missing climatological ice coverage data are included) Producer defined 1 Both partially covered ice measurements and likely ice-free measurements are included. Producer defined 2 All measurements are included, regardless of ice coverage. Producer defined waterbody_size A binary flag on waterbody size, indicating whether the river width is greater than 80 meters (node and reach data), reach length is greater than 7 kilometers (reach data), or the lake area is greater than 0.0625 square kilometers. Producer Defined 0 SWOT observation DOES meets waterbody size thresholds. Producer defined 1 SWOT observation does NOT meets waterbody size thresholds. Producer defined overall_quality Threshold based on the overall quality flag for reach, lake, and node level SWOT data. Producer Defined 0 Only 'good' measurements are included. Producer defined 1 Both 'good' and 'suspect' measurements are included. Producer defined 2 Both 'good', 'suspect', and 'degraded' measurements are included. Producer defined 3 All measurements are included. Producer defined bitwise_q Threshold based on the maximum allowed bitwise quality flag for reach, lake, and node level SWOT data, with bitwise value specifics detailed in the SWOT User Handbook. Producer Defined 0.0 inf xovr_cal_q Threshold based on the crossover calibration flag for reach, lake, and node level SWOT data. Producer Defined 0 Only 'good' crossover calibration measurements are included. Producer defined 1 Both 'good' and 'suspect' crossover calibration measurements are included. Producer defined 2 All measurements are included. Producer defined xtrk_flag A binary flag on cross track distance for a given SWOT observation, indicating the observation falls between 10 kilometers and 60 kilometers of the nadir path in either direction. Producer Defined 0 Observation falls between 10 and 60 km in either direction of the nadir path. Producer defined 1 Observation falls outside of 10 and 60 km in either direction of the nadir path. Producer defined partial_f A binary flag on whether the SWOT observation is partially or fully observed. All node measurements are considered to be fully observed. Producer Defined 0 Only full observed SWOT measurements are included. Producer defined 1 All measurements are included. Producer defined area_frac Minimum allowed fraction for the observed area, given by (area_detct/area_total), where the strictest bound is 0.75, and the most relaxed threshold is 0. Producer Defined 0.0 0.75 mean_abs_WSE_diff The mean absolute water surface elevation difference between SWOT and in situ water surface elevation across all unique paired sites after the given filters are applied. The difference is computed as the absolute difference between SWOT and an in situ observation after normalizing both time series by subtracting the median value. Producer Defined 0.005 7.288 meters median_R2 The median correlation coefficient between all unique paired sites, calculated from the correlation between SWOT water surface elevation and in situ water surface elevation after SWOT data have been filtered. Producer Defined 0.043 1.000 abs_WSE_diff_68 The 68th percentile of the absolute water surface elevation difference between SWOT and in situ water surface elevation across all unique paired sites after the given filters are applied. The difference is computed as the absolute difference between SWOT and an in situ observation after normalizing both time series by subtracting the median value. Producer Defined 0.000 0.6990 meters median_abs_WSE_diff The median absolute water surface elevation difference between SWOT and in situ water surface elevation across all unique paired sites after the given filters are applied. The difference is computed as the absolute difference between SWOT and an in situ observation after normalizing both time series by subtracting the median value. Producer Defined 0.000 0.295 meters percent_remaining Percentage of data remaining after the selected filters in a given row have been applied Producer Defined 0.006 92.207 SWOT_data_version Processing version of SWOT data Producer Defined C Version C SWOT products available from 2023-03-30 until 2025-05-03, representing an earlier version of SWOT data processing. Producer defined D The Version D products resolve several known issues in the Version C science data products, and is available from 2023-03-30 until present. Producer defined type SWOT data type, either river reach, river node, or lake Producer Defined reach SWOT river reach Producer defined node SWOT river node Producer defined lake SWOT lake Producer defined U.S. Geological Survey - ScienceBase mailing address

Denver Federal Center

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. description of file https://doi.org/10.5066/P1FE9W9E None 20260330 USGS - WATER Merritt E Harlan Mendenhall Researcher mailing and physical

Denver Federal Center, DFC Bldg 53

Lakewood CO 80225 (774)641-4099 mharlan@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998