In an effort to aid the prototype Earth-gauging system UCAR Google initiative, the NCSU Climate Modeling Laboratory is performing dynamical downscaling of operational forecasts for the West Africa region. For this, the Weather Research and Forecast Model (WRF) Version 2 is currently being tested for optimization purposes and to diagnose added value that dynamical downscaling may provide to operational forecasts.
Using the WRF climate mode at scales finer than the available coarse-scale
operational models (1 degree), we recognize that running the
model at 30km, for example, allows for the forecast of specific districts or
other geopolitical divisions within a country.
The figure below atests to the advantages of using finer scale forecasting.
The arrows point to a collection of 3 or 4 districts
in the southwest portion of the country of Niger and eastern Burkina-Faso as
portrayed by a World Health Organization (WHO)
meningitis alert map (left), and relative humidity in a WRF simulation at
30km resolution (top right) and NNRP1 reanalysis at 2.5km resolution (bottom right).
Some features to look at include the generalization in NNRP1 with larger
spacing between categories (i.e. 30-40% RH) whilst a
similar image from the WRF simulation has much more detailed spacing
between categories.
Also, notice how the drier, cooler colors cover a larger area of Niger
and Burkina-Faso. Because this particular type of meningitis has
been found to be so climate sensitive to changes in humidity regime,
such changes in relative humidity can offer valuable information
for stakeholders in the region in terms of supplies and transportation for inoculation purposes.
Efforts currently underway at UCAR will seek to use an ensemble of large scale models to provide operational forecasts for the Africa initiative. The NCSU Climate Modeling Laboratory will also explore the use of ensemble forecasting by downscaling each of the models in operational mode using WRF. Additionally, we will explore the relative skill and economic value of the ensemble prediction forecast using the recently published EROC method. Currently underway is a WRF climate mode ensemble using FNL initial conditions and varying physics in the model to simulate multiple model ensemble.