Simulation of temperature extremes over West Africa and the Eastern
Sahel with MPAS
Abstract
A large ensemble of 51 simulations with the Model for Prediction Across
Scales (MPAS) has been applied to assess its ability to reproduce
extreme temperatures and heat waves in the area of West Africa and the
Eastern Sahel. With its global approach the model avoids transition
errors influencing the performance of limited area climate models. The
MPAS simulations were driven with sea surface temperature (SST) and sea
ice extent as the only boundary condition.
The results reveal moderate cold biases in the range from -0.6° to -0.9°
C for the daily mean temperature and -1.4° to -2.0° C for the area mean
of the daily maximum temperature. The bias in the number of tropical
nights ranges from +3 to -10 days. An underestimation by up to 50% is
also present regarding the number of summer days. The heat wave duration
index is underestimated regionally by 10% to 60%. Compared to the
reanalyses, the biases revealed by the MPAS simulations are generally
smaller than with measured observational reference. The results from
long term runs and from short term runs with selected SST years are
similar.
Shortcomings in the reproduction of the temperature and precipitation
indices found in the present investigation indicate that the global MPAS
approach does provide a fidelity similar to that of the regional climate
models.