Abstract
Abstract. Understanding the propagation of prolonged meteorological drought helps solve the problem of intensified water scarcity around the world. Most of the existing literature studied the propagation of drought from one type to another (e.g., from meteorological to hydrological drought) with statistical approaches; there remains difficulty in revealing the causality between meteorological drought and potential changes in the catchment water storage capacity (CWSC). This study aims to identify the response of the CWSC to the meteorological drought by examining the changes of hydrological-model parameters after drought events. Firstly, the temporal variation of a model parameter that denotes that the CWSC is estimated to reflect the potential changes in the real CWSC. Next, the change points of the CWSC parameter were determined based on the Bayesian change point analysis. Finally, the possible association and linkage between the shift in the CWSC and the time lag of the catchment (i.e., time lag between the onset of the drought and the change point) with multiple catchment properties and climate characteristics were identified. A total of 83 catchments from southeastern Australia were selected as the study areas. Results indicated that (1) significant shifts in the CWSC can be observed in 62.7 % of the catchments, which can be divided into two subgroups with the opposite response, i.e., 48.2 % of catchments had lower runoff generation rates, while 14.5 % of catchments had higher runoff generation rate; (2) the increase in the CWSC during a chronic drought can be observed in smaller catchments with lower elevation, slope and forest coverage of evergreen broadleaf forest, while the decrease in the CWSC can be observed in larger catchments with higher elevation and larger coverage of evergreen broadleaf forest; (3) catchments with a lower proportion of evergreen broadleaf forest usually have a longer time lag and are more resilient. This study improves our understanding of possible changes in the CWSC induced by a prolonged meteorological drought, which will help improve our ability to simulate the hydrological system under climate change.
Highlights
Drought is one of the most damaging environmental disasters and has significant environmental, economic and social impacts around the world (Zhao and Running, 2010)
We present the methodology of this study, including (i) the identification of catchments with a long-term meteorological drought (Sect. 3.1); (ii) derivation of change in the catchment water storage capacity (CWSC) on account of drought based on the hydrologicalmodeling method (Sect. 3.2), including an introduction of the hydrological model adopted, the likelihood function, the model parameter estimation method and the identification method for the change points of the CWSC; and (iii) potential variables that might be associated with the changes in the CWSC (Sect. 3.3)
The results indicate that, under certain circumstances, a longterm meteorological drought would result in a significant change in the CWSC
Summary
Drought is one of the most damaging environmental disasters and has significant environmental, economic and social impacts around the world (Zhao and Running, 2010). It affects the balance of aquatic and terrestrial ecosystems and many economic and social sectors including agriculture yield, industrial production and urban water supply (Mishra and Singh, 2010). Recent literature indicates that improved probabilities of extreme events have been projected in many parts around the world because of increasing anthropogenic interference and global climate change, which implies more severe droughts in the future (Dai, 2011, 2012; Pan et al, 2019b). Pan et al.: The influence of a prolonged meteorological drought on catchment water storage capacity cyclonic storms and earthquakes, a drought may have a much longer duration
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