A diagnostic evaluation of precipitation 1 in CORDEX models over southern Africa

We evaluate the ability of ten regional climate models (RCMs) to simulate precipitation over southern Africa within the Cordex framework. An ensemble of ten regional climate simulations and the ensemble average is analysed to evaluate the model's ability to reproduce seasonal and interannual rainfall characteristics over regions of the subcontinent. All the RCMs use a similar domain, have a spatial resolution of ~50km and are driven by the ERA-Interim reanalysis (1989-2008). Results are compared against a number of observational datasets. The spatial and temporal nature of rainfall over the region is captured by all RCMs, however, individual models exhibit wet or dry biases over particular regions of the domain. Models generally produce lower seasonal variability of precipitation compared to observations and the magnitude of the variability varies in space and time. Model biases are related to the positioning of the ITCZ as well as moisture transport. The multi-model ensemble mean generally out-performs individual models, with bias magnitudes similar to differences across the observational data sets. In the northern parts of the domain some of the RCMs and the ensemble average improve the precipitation climate compared to that of the ERA-Interim reanalysis. The models are generally able to capture the dry (wet) precipitation anomaly associated with El Niño (La Niña) events across the region. Based on this analysis, we suggest that the present set of RCMs can be used to provide useful information on climate projections of rainfall over southern Africa.

KALOGNOMOU Evangelia-Anna;  LENNARD Christopher;  SHONGWE Mxolisi;  PINTO Izidine;  ALICE Favre;  KENT Michael;  HEWITSON Bruce;  DOSIO Alessandro;  NIKULIN Grigory;  PANITZ Hans-Juergen;  BUECHNER Matthias; 

2013-12-03

AMER METEOROLOGICAL SOC

JRC76595

0894-8755,   

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00703.1,    https://publications.jrc.ec.europa.eu/repository/handle/JRC76595,   

10.1175/JCLI-D-12-00703.1,