Early Career Researchers from UPGro Gro for GooD reflect on their time with the programme
What was your research focus in the Gro for Good project?
My work involved testing a new approach of creating a future rainfall time series for Mkurumudzi catchment in Kwale, with the ability to capture extreme high values. The aim is to better represent a future climate with more frequent and more intense extreme events as is expected under climate change. This approach is based on the use of a hybrid dynamic-statistical downscaling method, using the Advanced Delta Change (ADC) statistical method on multiple Regional Climate Models (RCMs). The studied RCMs are dynamically downscaled from the Coordinated Regional Climate Downscaling Experiment (CORDEX). Most studies on climate extremes focus on indices reflecting extremes in climate variables, such as consecutive dry/wet days, amount of rainfall in extreme wet days. However, most hydrological models require daily data as inputs. Thus, creating extreme rainfall time series allows us to evaluate the potential future effects on runoff. The analysis of the results showed that the Advanced Delta Change (ADC) transformation emulated the future changes in the upper tail of the distribution (90% quantile) better than the Classical Delta Change method. Moreover, increases/decreases in maximum rainfall generated from the ADC, respectively caused increases and decreases in the modeled maximum flow. Finally, model RACMOO22T-ICHEC produced the highest rainfall and flow and could be considered for studies involving extreme high rainfall scenario.
What fieldwork did you do in Kwale County and what data did you collect?
I visited Kwale County and went through the two main catchments Mkurumudzi and Ramisi. These visits aimed at getting a clear idea of the activities going on in the area and the available recorded hydroclimatic data over the last decades. The availability of runoff data allowed the selection of the Mkurumudzi catchment as study area and the ground stations rainfall data allowed the performance evaluation of the satellite data. We accessed the available data through Rural Focus Ltd and were able to locate the main sites of this research project.
How have you shared your work in Kenya?
From this work, two articles were published in an Open access journal and the whole report was catalogued in a thesis which is freely available on the PAUISTI Institute and JKUAT online repository and library.
What will you do next?
I am looking forward to continuing this research on the projection of low rainfall extremes and hydrological impacts, for enhancing drought studies.
- Ouédraogo, W.A.A.; Raude, J.M.; Gathenya, J.M. Continuous Modeling of the Mkurumudzi River Catchment in Kenya Using the HEC-HMS Conceptual Model: Calibration, Validation, Model Performance Evaluation and Sensitivity Analysis. Hydrology 2018, 5, 44.
- Ouédraogo, W.A.A.; Gathenya, J.M.; Raude, J.M. Projecting Wet Season Rainfall Extremes Using Regional Climate Models Ensemble and the Advanced Delta Change Model: Impact on the Streamflow Peaks in Mkurumudzi Catchment, Kenya. Hydrology 2019, 6, 76
Interview by Nancy Gladstone, SSEE, University of Oxford