Regional Climate Modelling over Southern Africa
Mary-Jane M. Kgatuke
South African Weather Service
The effect of topography
CSIRO GCM TOPO
MAX TEMP MAX TEMP
DARLAM TOPO
DARLAMCSIRO Atmospheric Research, Australia
Configuration over Africa
Africa 0º
30º
10º
20º
40º
0º 10º 20º 30º 40º 50º
100 x 100 grid points on a Lambert Conformal Projection(60x60 km resolution)
18 sigma layers in the vertical
Boundary values supplied by CSIRO9 (R21) AGCM – crosses
Semi-Lagragian advection & McGregor cumulus convection parameterization
Time step of 15 minutes integrating the hydrostatic equations forward in time
SIMULATES 30 DAYS IN 2 HOURS ON A LOCAL COMPUTER @ LRAM
Three 10-year regional model simulations forced by the global CSIRO-9 (R21) AGCM for the
A2 SRES scenario
2021 - 20301991 - 2000 2051 - 2060Basis climate
average over 10 years
REGIONAL SCALE CLIMATE CHANGE SCENARIO MODEL SIMULATIONS OVER SUB-
SAHARAH AFRICA
January 2021 - 2030 January 2051 - 2060
MAX TEMP ANOMALY MAX TEMP ANOMALY
MIN TEMP ANOMALYMIN TEMP ANOMALY
January 2021 - 2030 January 2051 - 2060
RAINFALL ANOMALY RAINFALL ANOMALY
MSLP ANOMALYMSLP ANOMALY
Models
• Models tend to be set up according to the performance of physical parameterizations chosen to represent different processes.
• The performance of the models will be different and therefore it is necessary to use different models for the same target area.
Models implemented in South Africa
• Regional climate studies– DARLAM at the University of Pretoria– RegCM2 at the South African Weather Service
• Short term forecasting at the South African Weather Service– ETA (operational)– MM5
RegCM2 over Southern Africa
• RegCM2 has been used to simulate tropical cyclone-like vortex tracks in the southern Indian Ocean
• Resolution:60 km
• Forcing fields: ECMWF
• Cumulus parameterization: Grell
• Time step :150 s
Objectives of the project with RegCM3(1)
• Examine the skill of RegCM3 in simulating regional climate over southern Africa.
• Determine the extent to which the simulations are compromised by errors in predicted SST’s and GCM output.
• Determine if RegCM3 is capable of simulating the variability between wet and dry periods.
Objectives of the project with RegCM3(2)
• Determine the skill of RegCM3 in capturing extreme rainfall events.
Thank you
