Analyses of rainfall extremes in East Africa based on observations from rain gauges and climate change simulations by CORDEX RCMs

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dc.contributor.authorOnyutha, Charles
dc.date.accessioned2022-09-14T19:13:48Z
dc.date.available2022-09-14T19:13:48Z
dc.date.issued2020
dc.description.abstractThis study derived twelve Extreme Rainfall Indices (ERIs) such as the Maximum Dry Spell (MDS) and Maximum Wet Spell (MWS) from daily rainfall observed over the period 1961–1990 at nine locations across East Africa. Capacity of six CO-ordinated Regional Climate Downscaling EXperiment (CORDEX) Africa Regional Climate Models (RCMs) driven by twenty six Climate Model Intercomparison Project phase 5 (CMIP5) General Circulation Models (GCMs) to reproduce the observed ERIs with respect to long-term mean and trends was evaluated. Four RCMs and their five driving GCMs were further analyzed with respect to ERIs. Ensemble means of the RCMs’ biases in simulating trends in several ERIs were of magnitudes above 50%. On average, biases in reproducing long-term mean were smaller than those for trends in ERIs. The difference between the performances of RCMs and GCMs depended on the selected RCM–GCM pair. The ensemble means of the RCMs reproduced observed ERIs better than the individual RCMs corroborating that the use of multi-model ensembles can boost credibility of climate change simulations and projections. The RCMs performed better than their driving GCMs in reproducing MDS. The biases of both the RCMs and GCMs were smaller in reproducing the MWS than MDS. Nonetheless, in reproducing observed MWS, the ensemble mean of RCMs’ biases was slightly larger than that of the driving GCMs indicating possible adding up of the uncertainties from the GCMs and RCMs. Suggested RCMs’ improvements regarding aerosol impacts on rainfall include adding missing constituents (like nitrate), and refining the crudely represented components. RCMs also require high resolution description (in both space and time) of land use types, land surface covers and characteristics as well as landscape heterogeneity. The GCMs to be used as the initial and lateral boundary conditions for the RCMs require improvement in their representation of key dynamical and thermodynamical feedbacks in the Tropical Indian Ocean.en_US
dc.identifier.citationOnyutha, C. (2020). Analyses of rainfall extremes in East Africa based on observations from rain gauges and climate change simulations by CORDEX RCMs. Climate Dynamics, 54(11), 4841-4864. https://doi.org/10.1007/s00382-020-05264-9en_US
dc.identifier.urihttps://doi.org/10.1007/s00382-020-05264-9
dc.identifier.urihttps://nru.uncst.go.ug/handle/123456789/4734
dc.language.isoenen_US
dc.publisherClimate Dynamicsen_US
dc.subjectCORDEX RCMsen_US
dc.subjectClimate changeen_US
dc.subjectEast african rainfallen_US
dc.subjectTrend analysisen_US
dc.subjectClimate change indicesen_US
dc.subjectCMIP5 GCMsen_US
dc.titleAnalyses of rainfall extremes in East Africa based on observations from rain gauges and climate change simulations by CORDEX RCMsen_US
dc.typeArticleen_US
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