资源环境科技发展态势分析平台

Changes in rainfall variability in future climate will pose challenges for adaptation. To evaluate changes in Asian-Australian monsoon wet season rainfall, daily data from historical and future (Representative Concentration Pathway RCP8.5) climate simulations are band pass-filtered to isolate variability on near-daily, weekly, monthly, intraseasonal, annual, interannual, and decadal time scales. This method is used to quantify changes in variability from 35 coupled climate models for each time scale over the Australian, South Asian, and East Asian monsoon domains. In nearly all cases, the median model change is positive, indicating increased rainfall variability, although with large model spread. The role of increased atmospheric moisture is examined by estimating the change due to an idealized thermodynamic enhancement. This enhancement produces increases in variability that are within the range of the simulated changes under the RCP8.5 scenario, indicating that thermodynamic responses provide a first-order explanation for the increased daily to decadal monsoon rainfall variability.