Coupled WRF-Hydro and Ufs Modeling to Improve Subseasonal-to-Seasonal Predictions

Errors in the representation of the land surface and hydrology in Earth system models can negatively affect atmospheric prediction, especially on Subseasonal to Seasonal (S2S) timescales on the order of weeks to months. This is due to slowly-varying land surface states, such as soil moisture and snowpack, which when included can increase forecast skill at the S2S timescales, and also provides more accurate initial conditions for atmospheric models. The NOAA Unified Forecast System (UFS) is a community-based, coupled, comprehensive Earth modeling system, which makes predictions from sub-hourly to seasonal timescales. The goal of this project is to improve the treatment of land surface-hydrology in UFS at S2S timescales by incorporating the WRF-Hydro model, which is a multi-scale, multi-physics hydrological model that also includes the Noah-MP land model. Specifically, we aim to improve the UFS model through improving land surface fluxes and freshwater discharge to the ocean, thereby closing the global water budget. This work will highlight the novel application of WRF-Hydro run globally at ~10 km spatial resolution in both uncoupled and coupled modes to UFS to improve S2S model prediction.