Uncertainty Quantification and Reliability Analysis of CMIP5 Projections for the Indian Summer Monsoon

A reliable Ensemble Averaging(REA) is a proposed technique which provides an estimate of Associated Uncertainty Range and Reliability of future climate change projections for Indian summer monsoon (June-September), simulated by the state of the art Coupled General Circulation Models (CGCMs) under Coupled Model Inter comparison Project 5 (CMIP5). An evaluation of historical as well as future (RCP4.5 scenario) simulations of ten CGCMs in the REA technique projects a mean monsoon warming of 1.2150C with an associated uncertainty range (±δ∆T) of 0.220C, and an all-India precipitation increase by 7.109 mm/ month with an associated uncertainty ((±δ∆P) of 2.592 mm/month for 2021–2050. REA technique also shows a considerable reduction in the uncertainty range compared with the simple average ensemble approach and is characterized by consistently high reliability index in a comparative study with individual CGCMs. The results suggest achievability of REA methodology in constituting the realistic future Indian Monsoon Projections by preparing a performance model and a descriptive confluence criteria.