A comprehensive comparison of the fifth and sixth phases of the coupled model intercomparison project based on the Canadian earth system models in spatio-temporal variability of long-term flood susceptibility using remote sensing and flood frequency analysis

Abstract

With the recent phase of the Coupled Model Intercomparison Project (CMIP), water professionals, especially flood modelers, are eager to examine how well climate models represent flood dynamics in the sixth phase of the CMIP (i.e., CMIP6) in comparison to the previous phase (i.e., CMIP5) and how will climate change affect them in the future. In this study, the results obtained from CMIP5 and CMIP6 based on the Canadian earth system models in calculating the amount of precipitation were compared, and the effect of these two reports on the amount of runoff was investigated. For this purpose, two models of CanESM2 and CanESM5 were used. The Flood Frequency Analysis (FFA) results indicated that the average Return Periods (RPs) calculated by the Annual Mean Discharge (AMD) for all distributions based on the CanESM5 are higher than those calculated by CanESM2. Besides, the average RPs by APD for all distributions except Log-Pearson3 calculated based on the CanESM5 are higher than those calculated by the CanESM2. For Monthly Mean Discharge (MMD), the average MMD calculated by CanESM5 is 2% higher than those for CanESM2. The Seasonality Mean Discharge (SMD) for CanESM2 in both summer (i.e., 0.37%) and spring (i.e., 6.8%) are larger than the CanESM5 values. The SMD for CanESM5 in both winter (i.e., 7.48%) and autumn (i.e., 4.72%) are larger than the CanESM2 values. For Monthly Peak Discharge (MPD) and Seasonality Peak Discharge (SPD), the difference between the flow discharges in CanESM2 and CanESM5 is significantly different based on the month or season as well as the station. The general comparison of the CanESM2 and CanESM5 indicates that the average MPD and average SPD related to the CanESM5 are 10% and 5% higher than those for CanESM2.