Climate Change Projections and Impacts on Future Temperature, Precipitation, and Stream flow in the Vea Catchment, Ghana
Gemechu Fufa Arfasa, Ebenezer Owusu-Sekyere, Dzigbodi Adzo Doke
Abstract
Climate change is a global issue, but the impact is not globally even. The Vea catchment is considered to be one of the regions at high risk from the impacts of climate change. The objective of this study was to project climate change and its impacts on temperature, precipitation and stream flow. Temperature and precipitation data of two stations were obtained from Ghana meteorological stations; in addition, precipitation data of twelve satellite stations were obtained from CHIRPS data with 0.05’ (5km) resolution to complement the in-situ datasets; and the temperature data for the satellite station obtained from the NASA power project. Modeled climate data were obtained from six GCMs in the CMIP6 data portal on the WCRP website under SSP 4.5 and SSP 8.5 emission scenarios. R software was used to extract NetCDF-format GCM data to Excel format and CMhyd was used for downscaling GCM data. The variance scaling method and local intensity scaling methods were used for temperature and precipitation bias correction, respectively. The Mann-Kendall (MK) method was used to determine the statistical significance of a change and identify trends in temperature and precipitation. The projected increases in average temperature range from 2.10 to 3.5°C under SSP4.5 and from 2.7 to 4.15°C under SSP8.5. Under the SSP4.5, annual average precipitation is anticipated to decrease by 12.34–13.1%, while the SSP8.5 projects a decrease of 12.6–13.6%. Under SSP4.5 and SSP8.5, the projected annual average streamflow decreases range from 28 to 37% and 36-42%, respectively. Results will help in the setting up of long-term water resource management strategies in the catchment as well as the development of appropriate adaptation methods to mitigate the ongoing impacts of climate change.