The CMIP5 projection of extreme climate indices in Indonesia using simple quantile mapping method

The amount of greenhouse gas emissions released during the combustion of fossil fuels directly affects the global temperature in the recent period. The assessment of future climate projections is necessary to plan mitigation and adaptation efforts in various sectors. For global warming studies, different scenarios based on the rate of radiative forcing and mitigation efforts in the future had been prepared as RCP or the Representative Concentration Pathways. In this study, two of the four scenarios will be used to project the future changes of climate parameters – the RCP8.5 scenario, where no mitigation effort is taken into account and the RCP4.5 scenario, which assumes the business-as-usual will still take place in the future. Observational data and Global Circulation Model (GCM) output from the Coupled Model Intercomparison Project 5 (CMIP5) are used to assess the future climate projection. The historical series of 29 models from GCM (Global Circulation Model) will be evaluated using daily observational data from 70 meteorological stations in Indonesia for 20 years period (1986 – 2005) based on the similarity of its spatial and temporal patterns. The output of GCMs is bias-corrected before being used in the analysis process, using quantile mapping method. Five models are chosen based on the correlation values to project the extreme climate events over the Indonesia region, using the Expert Team on Climate Change Detection and Indices (ETCCDI), or the extreme climate indices. The indices used are the total annual rainfall (Prcptot), consecutive dry days (CDD), consecutive rainy days (CWD), monthly maximum temperature values (TXx) and monthly minimum temperature values (TXn). Compared to the baseline period (1981 – 2010), most of the extreme climate events will be increased significantly in the future periods (2011 – 2040, 2041 – 2070, 2071 – 2100), except for CDD.