Climate driver informed short-term drought risk evaluation

This study proposes a methodology for quantifying the impact of climate drivers on water supply drought risk. Climate driver informed short-term drought risks are evaluated for future time steps following conditioning on the initial state of climate drivers and initial reservoir storage level. The methodology is demonstrated using a case study in eastern Australia. Simulations of future rainfall are provided by the climate-informed multitime scale stochastic (CIMSS) model, which is used to incorporate Pacific decadal variability exhibited by the Pacific Decadal Oscillation-Interdecadal Pacific Oscillation. The climate driver informed drought risks are compared to a traditional approach that evaluates longterm drought risks using a nonclimate driver informed rainfall model. The case study considers four scenarios describing a range of different climate driver initial conditions. For the PDO-IPO positive initial state scenarios, the short-term risks are found to be higher than traditional long-term risks by 20%–100%. Furthermore, the elevated short-term risks can last up to 30 years with the CIMSS model but