Statistical downscaling of future rainfall and temperature under different canesm2-RCP model scenarios

Abstract

The current study downscaled daily rainfall and temperature from Canadian Second Generation Earth Systems Model (CanESM2) in Uasin-Gishu County. The main objective of the study was to determine the future daily rainfall and temperature characteristics projected form the Global Climate Model (GCM) under two representative concentration pathways (RCP 4.5 and RCP 8.5). Outputs from GCMs are of a coarser resolution and therefore require downscaling to local scales to allow for practical applications in specific areas of interest. Methodology for the study involved: (1) estimation for the missing data; (2) analysis of the current climate characteristics; (3) screening of predictor variables; (4) statistical synthesis of climate from the statistical downscaling model (SDSM); and (5) analysis of the projected climate characteristics. The results from the present climate show that both rainfall and temperature have been increasing over time since the year 1974 to 2017 with a change of 2.4 mm and 0.010C correspondingly. The future downscaled climate indicated a downward and an upward trend for temperature and rainfall respectively from the year 2006 to 2099 under both RC P4.5 and RCP 8.5. The model was quite skillful. There was a substantial amount of missing data and recommend augmentation with the remote sensed climate from satellites in the future studies. The warming consistency over the study area points to a possible insurgence of malaria causing mosquitoes (highland malaria), which will be a threat to the health of people of Uasin-Gishu County and its neighbourhoods. Also due to increasing temperatures, there will probably be increased and alternating frequencies of above and below normal rainfall. Since Eldoret town is experiencing rapid development, it implies that there is a corresponding increment in land area under concrete surface. What this means, in an event of above normal rainfall, is that there will be flooding. It is advised that the road, building and construction sectors

consider redesigning bridges, run-off pathways and related structures to accommodate for the coming flooding menace.