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Geoffrey Sabiiti


Evaluation of the performance of the UK Met Office's Regional Climate Models (RCMs) over the Greater Horn of Africa (GHA)

Description of CSRP research

Climate information from regional climate models (RCMs) is vital for assessing region specific climate impacts. Such information is, however, associated with errors in simulating key climatic variables especially precipitation on smaller spatial scales. This study has been undertaken to understand the systematic errors associated with the UK Met Office RCMs outputs over the Greater Horn of Africa (GHA) region. These RCMs include a regional version of the newly developed Hadley Centre's Global Environmental Model version 3 (HadGEM3) and the HadRM3P RCM (based on the earlier HadCM3 global model). The latter RCM is run separately with two distinct Met Office Surface Exchange Schemes (MOSES1 and MOSES2). The performance of the Met Office RCMs has also been compared against two RCMs from the CORDEX (Coordinated Regional Downscaling Experiments) over the Africa domain. The RCM experiments were run at ~50 km resolution for the period 1989-2008 and used the ERAINTERIM dataset to provide the lateral boundary conditions.

The newly developed Willmott refined index of model performance, the mean percentage bias, the mean absolute error, root mean square error and the Pearson's product moment correlation coefficient will be used as statistical measures for model performance. These metrics also aid inter-comparisons between different models and observational data sets across spatial and temporal scales in the region.

The study also evaluates the future climate projections from the PRECIS RCM downscaled experiments. The RCM outputs will be based on a subset of the 17-member perturbed-physics ensembles (HadCM3Q0 - Q16) of the Quantifying Uncertainties in Models Predictions (QUMP) project. Future temporal and spatial patterns in rainfall and temperature distributions over GHA regions will be investigated and discussed.

The CSRP project feeds into PhD research at the University of Nairobi, which entails investigation of existing and potential linkages between banana productivity and variations in climate in Uganda. The research will also investigate performance of the regional climate models and evaluate impacts associated with PRECIS regional model projections on future banana productivity in Uganda. The PhD research will also evaluate adaptation strategies in Uganda's banana agricultural subsector for sustainable banana productivity in Uganda.

Career background

Geoffrey Sabiiti attended Makerere University and attained a Bachelor of Science degree with a specialization in Mathematics in 2003. He was lectured many Unit but most relevant now are Dynamical Systems, Differential Equations and Numerical analysis. He also attended a Postgraduate in Meteorology at Makerere University 2005/06 and in 2008, he completed an MSc. in Meteorology at the University of Nairobi. His graduate training and research has enabled him to gain good understanding of atmospheric systems and climate modeling skills. He now specializes in evaluation of climate performance over Eastern Africa. He has since acquired good computational skills and basic knowledge in programming using C++.

He holds a position as lecturer in the Department of Geography, Geo-informatics and Climatic Studies of Makerere University in Uganda.

More about Geoffrey Sabiiti

Areas of particular interest and expertise

  • Regional climate processes
  • East Africa rainfall variability
  • RCM output error analysis
  • Climate Change, Impacts and Adaptation (agricultural sector)

Based at: The IGAD Climate Prediction and Applications Centre (ICPAC), Nairobi, Kenya.

This research project aligns with theme 2 of the CSRP Fellowship scheme: Downscaling investigations and applications

Geoffrey Sabiiti is working in collaboration with Wilfran Moufouma-Okia of the UK Met Office.

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