Implementation of a Coupled Land-atmosphere Modeling System within a Northwestern Mexican River Basin

Fully coupled modelling of atmospheric and hydrological processes is of growing interest among the hydrometeorology community, due to the importance of comprehending feedback processes that occur at the land-atmosphere boundary conditions; for example, mechanisms relating soil moisture conditions to rainfall events within a land–atmosphere modelling system. A better understanding of these atmosphere-land interactions can improve our ability to foreshadow process representation of the water cycle modeling system.

On the other hand, a coupled land-atmosphere modeling system can offer potential predictability for both medium and long range weather forecasting. The memory range between land surface processes and atmosphere processes differ in nature, the first having a longer memory than the other. Consequently, understanding multi-time scale processes within a land-atmosphere modelling system is of importance for improving forecast between medium-range and seasonal forecasts. Improving forecast capabilities between sub-seasonal to seasonal forecasting, can help shape the design of strategies and programs for water resource management, flood risk management, water supply and irrigation design.

In this study, we conduct coupled land-atmosphere simulations within a large river basin in northwest México, for an extreme hidro-meteorological event that occurred in September 2018, simulating precipitation and runoff observed during the extreme event, through the use and implementation of the fully coupled WRF/WRF-Hydro modeling system. Firstly, the WRF-Hydro modelling system is tested as a stand-alone hydrological model (not coupled to WRF model) for parameter calibration and validation using observed streamflow data, and purposely assessing model reliability for the study area. Secondly, fully coupled land-atmosphere simulations are conducted during a 2 year long simulation (prior to the extreme event of September 2018) in the Sinaloa Hydrologic Region. Additionally, we compare stand-alone model and coupled WRF/WRF-hydro model simulations for three simulated variables: precipitation, runoff and soil moisture. Lastly, to assess the performance of the coupled WRF/WRF-Hydro model, we compare observed and simulated hydrographs for the simulated period event.