The Role of Rivers in Ocean Forecasting

Abstract. The connection between the ocean and the land is made possible thanks to rivers, which are a vital component of the Earth's system. They govern the hydrological and biogeochemical contributions to the coastal ocean and influence local circulation and the distribution of water masses, modulating processes such as upwelling and mixing. This paper provides an overview of recent advancements in river modelling, with a particular focus on estuaries. The methods discussed range from those currently adopted in coarse-resolution ocean forecasting systems, where mixing processes are primarily parameterized, to coupling approaches that are better suited for coastal systems. A review of river data availability is also presented, illustrating various sources, from observational data to climatological datasets, and more precise river modelling approaches that are improving the representation of water discharges in operational systems. Finally, a compendium of current operational systems is provided, with a focus on how river forcing is treated, from global to coastal scales.