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
- 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.,
- 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.