This study updates design rainfalls for the Brisbane River Basin, Australia, employing rainfall data from eight CMIP5 General Circulation Models (GCMs) across two Representative Concentration Pathways (RCP 4.5 and RCP 8.5) and four future timeframes (2016–2045, 2036–2065, 2056–2085, and 2075–2104), totalling 64 climate futures. Future design rainfalls were computed for Annual Exceedance Probabilities (AEPs) of 1%, 2%, 5%, and 10%, spanning durations from 1 to 7 days. For each climate future, an Annual Maximum Series was established, and a Gumbel distribution was applied to estimate precipitation for various AEPs. Comparisons were made with baseline (stationary) design rainfalls and those derived from Australian Rainfall & Runoff (AR&R) methodology based on temperature scale factors. GCM-derived design rainfalls indicate a general reduction in depths for most durations and AEPs under both RCP scenarios. Specifically, RCP 4.5 demonstrated significant reductions in design rainfalls for the 1% AEP, ranging from −9.61% (1-day duration) to −21.40% (7-day duration). Similarly, RCP 8.5 showed decreased depths, except for 1-day, 2-day, and 3-day design rainfalls in the 2075–2104 timeframe, which exhibited marginal increases. AR&R methodology yielded substantially higher design rainfalls, with increases reaching +11.6% for 1% AEP and 10% AEP. While GCM-derived rainfalls imply adequacy of current drainage infrastructure, AR&R methodology suggests a more conservative estimate, emphasizing the need for cautious climate data interpretation.

中文翻译：

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澳大利亚昆士兰州东南部气候变化情景下的设计降雨量：布里斯班河案例研究

本研究更新了澳大利亚布里斯班河流域的设计降雨量，采用了来自两个代表性浓度路径（RCP 4.5 和 RCP 8.5）和四个未来时间范围（2016-2045 年、2036-2065 年、2036-2065 年）的 8 个 CMIP5 大气环流模型 (GCM) 的降雨数据。 2056-2085年和2075-2104年），总共64个气候未来。未来设计降雨量按年超额概率 (AEP) 1%、2%、5% 和 10% 计算，持续时间为 1 至 7 天。对于每种气候未来，建立了年度最大序列，并应用甘贝尔分布来估计各种 AEP 的降水量。与基线（固定）设计降雨量和基于温标因子的澳大利亚降雨和径流（AR&R）方法得出的降雨量进行了比较。 GCM 得出的设计降雨量表明，在两种 RCP 情景下，大多数持续时间和 AEP 的深度普遍减少。具体而言，RCP 4.5 表明，1% AEP 的设计降雨量显着减少，范围从 -9.61%（1 天持续时间）到 -21.40%（7 天持续时间）。同样，RCP 8.5 显示深度下降，但 2075-2104 年期间的 1 天、2 天和 3 天设计降雨量除外，这些降雨量显示出边际增加。 AR&R 方法产生了显着更高的设计降雨量，1% AEP 和 10% AEP 的增幅达到 +11.6%。虽然 GCM 得出的降雨量意味着当前排水基础设施充足，但 AR&R 方法提出了更为保守的估计，强调需要谨慎地解释气候数据。