Appropriately treating riverine freshwater discharge into the oceans in Earth system models is a challenging problem. Commonly, the river runoff is discharged into the ocean models with zero salinity and arbitrarily distributed either horizontally or vertically over several grid cells. Those approaches entirely neglect estuarine physical processes that modify river inputs before they reach the open ocean. In order to realistically represent riverine freshwater inputs in Earth system models, a physically based Estuary Box Model (EBM) is developed to parameterize the mixing processes in estuaries. The EBM represents the estuary exchange circulation with a two-layer box structure. It takes as input the river volume flux from the land surface model and the subsurface salinity at the estuary mouth from the ocean model. It delivers the estuarine outflow salinity and net volume flux into and out of the estuary to the ocean model.

Sun, Q., M. M. Whitney, F. O. Bryan, and Y. -heng Tseng, 2017: A box model for representing estuarine physical processes in Earth system models. Ocean Modelling, 112, 139-153, doi:10.1016/j.ocemod.2017.03.004.

Sun, Q., M. M. Whitney, F. O. Bryan, and Y. -heng Tseng, 2018: Assessing the Community Earth System Model (CESM) performance in the coastal ocean relative to a new climatology. J. Advances in Modeling Earth Systems, submitted.  Supplementary Information.