Operational Dust Prediction - Mineral Dust: A Key Player in the Earth System - page 234

topographic source function and uses a wind speed threshold for dust emissions.
The dust particle-size distribution is discretised into five bins. Further description
of the aerosol module, its implementation in the GEOS modelling system and
its performance is provided in Colarco et al. ( 2010 ). The current version of the
GEOS-5 forecasting system performs twice daily 5-day forecasts at 0.25 ı 0.3125 ı

latitude/longitude horizontal resolution in a quasi-operational framework. AOD
based on MODIS observations are assimilated in a 3D-Var framework.

NCEP/NGAC Global Aerosol Forecasting System

Since September 2012, NOAA NCEP has provided 5-day global dust forecasts once
per day (at 00 UTC cycle) from the NEMS GFS Aerosol Component (NGAC)
system. The forecast model is the Global Forecast System (GFS) within the
NOAA Environmental Modeling System (NEMS), and the aerosol component is
GOCART. The development of NGAC is part of NCEP's modelling efforts towards
a unified modelling framework. The GOCART parameterisations, developed and
implemented within GMAO's GEOS-5 Earth system model (Colarco et al. 2010 ),
were coupled with NCEP's NEMS GFS to establish the first interactive atmospheric
aerosol forecasting system at NCEP (Lu et al. 2010 , 2013 ). While the ultimate goal
at NCEP is a complete Earth system model with the inclusion of aerosol-radiation
feedback and aerosol-cloud interaction, the current operational configuration is to
maintain a low-resolution forecast-only system for aerosol prediction and a high-
resolution forecasting and analysis system for medium-range NWP.

NMMB/BSC-Dust Model

The NMMB/BSC-Dust model (Pérez et al. 2011 ) is the global and regional dust
forecast operational system developed and maintained at the Barcelona Super-
computing Center-Centro Nacional de Supercomputación (BSC-CNS). It is an
online multi-scale atmospheric dust model designed and developed at BSC-CNS
in collaboration with NOAA NCEP, NASA Goddard Institute for Space Studies and
the International Research Institute for Climate and Society (IRI). The dust model
is fully embedded into the Non-hydrostatic Multiscale Model (NMMB) developed
at NCEP (Janjic et al. 2011 and references therein) and is intended to provide
short- to medium-range dust forecasts for both regional and global domains. The
NMMB/BSC-Dust model includes a physically based dust emission scheme, which
explicitly takes into account saltation and sandblasting processes. It includes an 8-
bin size distribution and radiative interactions. The NMMB/BSC-Dust model has
been evaluated at regional and global scales (Pérez et al. 2011 ; Haustein et al. 2012 ).
These developments represent the first step towards a unified multiscale chemical-
weather prediction system at BSC-CNS (NMMB/BSC-CTM; Jorba et al. 2012 ).