MERIT-SWORD: Enabling Bidirectional Data Transfer Between MERIT Hydro Basins and the SWOT River Database (SWORD)

The recently launched Surface Water and Ocean Topography (SWOT) Mission will provide transformative observations of water surface elevation, width, and slope and estimates of discharge for global rivers in the SWOT River Database (SWORD). Here, we develop links between the river reaches of SWORD and MERIT Hydro Basins (MHB), a vector hydrography dataset based on the MERIT digital elevation model and MERIT Hydro hydrography maps, to enable interoperability between SWOT vector data products and hydrologic modeling frameworks. This dataset, termed MERIT-SWORD, identifies a subset of ~277,000 global MHB river reaches that most closely represent the location and extent of the SWORD river network and establishes bidirectional, one-to-many translations between reaches in the two hydrography datasets. The dataset also provides an evaluation of the accuracy of translations between SWORD and MHB reaches using several diagnostic flags, which highlight reaches where the links between the datasets may be absent or of reduced quality. Our open-source data product (Zenodo Link) will serve to unite SWOT observations with river routing models, allowing for the seamless and standardized assimilation of SWOT vector products into global river simulations and the provision of improved a priori discharge estimates for SWOT discharge computation.