Enoch Bessah, Speaker at Climate Change Conference
Kwame Nkrumah University of Science and Technology, Ghana
Title : Extreme changes of daily rainfall and temperature patterns in a tropical sub-humid basin A statistical downscaling assessment for the 21st century

Abstract:

Climate change has exacerbated the occurrence of extreme weather events in many regions worldwide. The objective of this study was to assess extreme temperature and rainfall variations in the Pra River Basin (a tropical sub-humid basin in Ghana), as a case-study potentially applicable to other similar regions globally. The methodology was based on the use of different climate models. Firstly, we tested the capability of the statistical downscaling model SDSM-DC to simulate past extreme climate indices for the period 1981 – 2010 (observed). We then projected temperature indices for the period 2011 – 2100 under CMIP5 RCP4.5 and 8.5 emission scenarios in the basin. Ten rainfall and nine temperature extreme indices were examined and the accuracy of SDSM-DC was evaluated with the Nash-Sutcliffe efficiency and Percent bias. The results show that observed number of heavy precipitation days increased, whilst consecutive wet days and consecutive dry days decreased, although the trend was not significant. Moreover, observed warm and cool temperature generally showed a significant increasing and decreasing trend, respectively. Performance analysis shows that SDSM-DC had a poor accuracy level in simulating rainfall indices; however, whilst simulating TX90p, TX10p, TN10p and DTR, the model was acceptable at more than 50% of the stations. Generally, TX90p showed a significant increasing trend, whereas TX10p, TN10p and DTR showed a significant decreasing trend between 2011 and 2100 under both RCP4.5 and 8.5. By 2100, under the RCP4.5 scenario, TX90p, TX10p, TN10p and DTR could increase by 0.72%, 0.36%, 0.35% and decrease 0.08°C respectively; whereas under the RCP8.5 scenario it could increase by 0.73%, 0.32%, 0.34% and decrease 0.15°C respectively. Therefore, the continuous warming trend poses threat to water resources, food security (including pest invasion, e.g. armyworms) and human health in the basin. The findings are relevant for adaptation and management policies and strategies planning. They also provide insights for improving climate models’ capabilities to simulate extreme climate indices at local and regional scales. Analogous simulations in other regions within Ghana and other nations, especially in Sub-Saharan Africa, could help improve the accuracy of these prediction models.

Biography:

Dr. Enoch Bessah studied BSc. Agricultural Engineering at the Kwame Nkrumah University of Science and Technology (KNUST), Ghana and graduated in 2011. He then joined the department of the university as a Teaching and Research Assistant for one year and studied MTech in Climate Change and Adapted Land Use at the Federal University of Technology, Minna in Nigeria and graduated in 2014. Enoch received PhD in Environmental Management from Pan African University and University of Ibadan, Nigeria in 2019. He is currently lecturing at KNUST. Enoch has about 10 peer-reviewed publications.

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