Publication Abstracts

Druyan and Fulakeza 2013

Druyan, L.M., and M. Fulakeza, 2013: Downscaling reanalysis over continental Africa with a regional model: NCEP versus ERA Interim forcing. Clim. Res., 56, 181-196, doi:10.3354/cr01152.

Five annual climate cycles (1998-2002) are simulated for continental Africa and adjacent oceans by a regional atmospheric model (RM3). RM3 horizontal grid spacing is 0.44° at 28 vertical levels. Each of 2 simulation ensembles is driven by lateral boundary conditions from each of 2 alternative reanalysis data sets. One simulation downscales National Center for Environmental Prediction reanalysis 2 (NCPR2) and the other the European Centre for Medium Range Weather Forecasts Interim reanalysis (ERA-I). NCPR2 data are archived at 2.5° grid spacing, while a recent version of ERA-I provides data at 0.75° spacing. ERA-I-forced simulations are recommended by the Coordinated Regional Downscaling Experiment (CORDEX). Comparisons of the 2 sets of simulations with each other and with observational evidence assess the relative performance of each downscaling system. A third simulation also uses ERA-I forcing, but degraded to the same horizontal resolution as NCPR2. RM3-simulated pentad and monthly mean precipitation data are compared to Tropical Rainfall Measuring Mission (TRMM) data, gridded at 0.5°, and RM3-simulated circulation is compared to both reanalyses. Results suggest that each downscaling system provides advantages and disadvantages relative to the other. The RM3/NCPR2 achieves a more realistic northward advance of summer monsoon rains over West Africa, but RM3/ERA-I creates the more realistic monsoon circulation. Both systems recreate some features of July-September 1999 minus 2002 precipitation differences. Degrading the resolution of ERA-I driving data unrealistically slows the monsoon circulation and considerably diminishes summer rainfall rates over West Africa. The high resolution of ERA-I data, therefore, contributes to the quality of the downscaling, but NCPR2 lateral boundary conditions nevertheless produce better simulations of some features.

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BibTeX Citation

@article{dr09300j,
  author={Druyan, L. M. and Fulakeza, M.},
  title={Downscaling reanalysis over continental Africa with a regional model: NCEP versus ERA Interim forcing},
  year={2013},
  journal={Clim. Res.},
  volume={56},
  pages={181--196},
  doi={10.3354/cr01152},
}

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RIS Citation

TY  - JOUR
ID  - dr09300j
AU  - Druyan, L. M.
AU  - Fulakeza, M.
PY  - 2013
TI  - Downscaling reanalysis over continental Africa with a regional model: NCEP versus ERA Interim forcing
JA  - Clim. Res.
VL  - 56
SP  - 181
EP  - 196
DO  - 10.3354/cr01152
ER  -

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