Evaluation of the High Resolution Rapid Refresh (HRRR) Model Using Near-Surface Meteorological and Flux Observations

The High Resolution Rapid Refresh (HRRR) model became operational at the National Center for Environmental Prediction (NCEP) in 2014 but the HRRR’s performance over certain regions of the coterminous US has not been well studied. In this work, we evaluated how well version 2 of the HRRR simulates near-surface meteorological fields and the surface energy balance. We evaluated the 1-, 3-, 6-, 12-, and 18-h HRRR forecasts, as well as the HRRR’s initial conditions, i.e. the 0-h fields, using meteorological and flux observations. These observations were obtained from towers installed in northern Alabama to support the Verification of the Origins of Rotation in Tornadoes Experiment in the Southeast U.S. (VORTEX-SE) and from northern Oklahoma at the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site.

During the 8-month model evaluation period in northern Alabama, i.e. from 1 September 2016 through 30 April 2017, we found that the HRRR accurately simulated the observations of near-surface air and dew point temperature (R² > 0.95). When comparing the HRRR output with the observed sensible, latent, and ground heat flux, we found that the agreement was weaker (R² ≈ 0.7), and the root mean square errors were much larger than those found for the near-surface meteorological variables. The results from Alabama were consistent with those from the DOE ARM SGP flux towers and further underscored important time-of-day biases present in the HRRR. The consistent results between Alabama and Oklahoma help motivate the need for additional work to improve the representation of surface fluxes and their coupling to the atmosphere in future versions of the HRRR.