Optimal Long-term Rainfall Trends Prediction under Climate Change Scenarios in Small Basin: Case study Sedon Basin, Lao PDR

Abstract

This research aims to predict the long-term rainfall trends under climate change (CLiM) within the next 30 years (2021–2050) under greenhouse gas emissions (GHGs) of two Representative Concentration Pathway; RCP) scenarios namely, moderate (RCP4.5) and very high (RCP8.5) from the Mixed Resolution version of the Max Planck Institute Earth System Model (MPI-ESM-MR). The climatic data (rainfall) from MPI-ESM-MR was bias corrected by employing Climate Model data for hydrologic modeling (CMhyd). Three of bias correcting methods such as linear scaling (LS), delta change (DC), and power transformation of precipitation (PTP) were used. The result of the research indicated that the monthly and annual rainfall in the future under the RCP4.5 and RCP8.5 scenarios will likely increase, and the RCP8.5 will be higher than RCP4.5 on average of 3%. This difference value suggests that the managing water under RCP8.5 should enhance the degree of management than one of RCP4.5. The RCP4.5 was projected the monthly rainfall to increase and decrease between -57 and 345% and a rainfall trend between -0.467 and 0.31mm/year. The RCP8.5 was expected to increase and decrease between -54 and 174% and its trends between -0.175 and 0.177 mm/year. The changes in annual rainfall are between -26 and 14% (RCP4.5) and -24 and 21% (RCP8.5). The trend of annual rainfall is positive for both RCP4.5 and RCP8.5, with trend 0.075 and 0.092 mm/year, respectively. Key finding from this conducted will be essential for the researcher and water resources scholar’s Laos.