This study investigates whether low flow events in a catchment exhibit a possibility of switching regimes. If this happens, it can result in a catchment experiencing a flow anomaly that is even more extreme than what was historically considered a conventional low flow event. A Hidden Markov Modeling approach was used to identify shifts in the intensity of low flow events in catchments in southeast Australia. We found very strong evidence of low flow intensity exhibiting two distinct states (viz., a normal and an intensified state) for several catchments, providing convincing reasons to believe that low flows can and have undergone regime changes. The periods when the catchments exist in an intensified low flow state were associated with higher maximum and average monthly temperature (, respectively) and lower precipitation (, a decline of 30%) compared to periods when these exist in their normal state.

中文翻译：

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澳大利亚东南部流域多个低流量状态的存在

本研究调查流域内的低流量事件是否表现出切换状态的可能性。如果发生这种情况，可能会导致流域出现流量异常，甚至比历史上认为的传统低流量事件更为极端。隐马尔可夫模型方法用于识别澳大利亚东南部流域低流量事件强度的变化。我们发现了非常有力的证据，表明几个流域的低流量强度表现出两种不同的状态（即正常状态和强化状态），这提供了令人信服的理由来相信低流量可以并且已经经历了状态变化。与正常状态下的时期相比，流域处于强化低流量状态的时期与较高的最高月平均温度（分别）和较低的降水量（下降 30%）相关。