Exploring Land-Atmosphere Interactions in the Unified Forecast System using the Common Community Physics Package Single Column Model (CCPP-SCM)

The Unified Forecast System (UFS) is a comprehensive, community-developed Earth modeling system, designed as both a research tool and as the basis for NOAA’s operational forecasts. The Developmental Testbed Center (DTC), which has the overarching goal of making the Research-to-Operations (R2O) pipeline more efficient, has been tasked by the U.S. NOAA Next Generation Global Prediction System (NGGPS) program to develop a Common Community Physics Package (CCPP), which aims at lowering the bar for community scientists to conduct tests and contribute innovations to be considered for operational implementation.

The land-atmosphere (L-A) system is comprised of the soil, vegetation, and the lowest layer of the atmosphere. Processes that transport energy and moisture within the L-A system contribute to the structure and diurnal evolution of the planetary boundary layer (PBL), the layer between the land surface and the free troposphere. By influencing the state of the PBL, biases in L-A model parameterizations can negatively impact weather forecast skill. For example, differences in surface properties, such as soil moisture and vegetation, can impact PBL evolution during the morning transition and the growth of the PBL later in the day, impacting forecasts of air quality, cloudiness, and precipitation.

Here, we assess the representation of processes within the L-A system in UFS over the Continental United States. We use the CCPP Single Column Model (SCM) forced by the NOAA’s UFS model output, testing UFS physics prototypes regarding the representation of diurnal evolution of PBL and near-surface state variables. Cases explored in this study represent a range of vegetation types and soil moisture conditions across different seasons. This study will provide insight into model strengths and deficiencies and suggests the importance of physical processes that represent PBL and their role in L-A interactions.