How would climate change affect Texas Coast — A model design for alkalinity in one estuary

Abstract

To better understand the influence of climate change, a total alkalinity model is needed since Texas Coast has been experiencing a long-term acidification during past decades. The entire model will include three sub-models: water transport, evaporation and biochemical reactions. In this study, we developed a transport model for one Texas estuary derived from Advanced Circulation Model (ADCIRC), and improved it based on our studying estuarine hydrologic conditions. This transport model solves the Nueces Estuary hydrodynamics by directly considering the change of flow velocity from tides, and this approach will be very computationally demanding for chemical transport. Tidal cycling will be accounted for using the concept of longitudinal dispersion, which can be calculated from the difference between the actual and mean flow velocities. The simulated results well matched with real-time monitoring data, which shows its applicability on modeling the hydrologic condition of this estuary. In addition, the results indicate this estuary is ocean-dominated, it also shows a long-term acidification potential resulted from diminishing riverine inflow and advection of more acid Gulf of Mexico seawater.