Rapid Refresh with Chemistry

Real time forecasts predicting weather and air quality

The Rapid Refresh model is used to forecast weather air pollution. The model is based on the Weather Research and Forecasting coupled with chemistry (WRF-Chem). Major components and details of the model include:

A 48-hour forecast is run once per day, initialized at 06 UTC
13 km horizontal resolution, 51 vertical levels extending to 50 hPA
Advective chemical transport performed simultaneously with the meteorology (i.e., "online")
Reduced carbon-bond gas-phase chemical mechanism (based on Houweling et al. 1998) coupled to a simplified version of MADE/VBS-SOA (Ahmadov et al., 2012)
Anthropogenic emissions modified to reflect reduced activity due to COVID using: NEI-2017, CEMS, FIVE, FOG, CEDS-2017
Daily varying wildfire emissions and plumerise of gases and aerosols constructed from daily measurements of satellite fire radiative power (FRP), similar to RAP-Smoke and HRRR-Smoke.
Online biogenic emissions with BEIS (presently only over NA)
Online dust emissions with the AFWA (LeGrand et al., 2018)
Online sea salt emissions
N2O5 heterogenous loss and ISORROPIA v2.1
Inline non-local vertical mixing with MYNN
Photolysis with TUV
RRTMG shortwave and longwave radiation
Aerosol direct effects on radiation and photolysis
Convective and turbulent chemical transport
Dry deposition and convective and resolved wet removal of gases and aerosols
Initial and boundary meteorological conditions from GFS with additional data assimilation from the experimental RAP forecast running at ESRL.
Cycling of chemical and land surface fields; chemical boundary conditions are static WRF-Chem profiles.

For a more detailed description of the meteorology model, one may go to the Rapid Refresh model web page or to the WRF/Chem web page for a description of the chemistry model.

The figure above shows the surface PM 2.5 Aerosol Dry Mass loop from October 17-18, 2020

In addition to the forecasts shown below, the High-Resolution Rapid Refresh with fire smoke (HRRR-Smoke) is being run in real time on a high resolution domain (3km resolution) over the CONUS domain. Output from the forecasts are available under the HRRR-Smoke web page.

The RR-Chem forecasts are run twice a day - 00 and 12 UTC. A few plots from the model forecasts are provided below.

A 13 km air quality forecast runs out to 48 h with 3 h forecast intervals.

13 km RR-CHEM air quality and weather forecast using RACM-SOA-VBS (modal aerosols)

This model is run on NOAA/ESRL's 64-bit supercomputer. Meteorological initial and boundary conditions come from the GFS model forecasts. For air quality forecasts, the chemistry fields produced by a previous 12 h forecast are used to initiallize each new forecast. Anthropogenic emissions data for CONUS are from an improved EPA NEI-11 (National Emissions Inventory, 2011) data set with RETRO/EDGAR emissions used elsewhere.