Response of catchment water storage capacity to the prolonged meteorological drought and asymptotic climate variation

Abstract

Abstract. Studies on the hydrological response to continuous extreme and asymptotic climate change can improve our ability to cope the intensified water-related problems. Most of the existing literature focused on the runoff response to different climate change patterns, while neglected the impacts by the potential variation in the catchment water storage capacity (CWSC) that plays an important role in the transfer of climate input to the catchment runoff. This study aims to identify the response of the CWSC to the long-term meteorological drought and asymptotic climate change systematically. Firstly, the time-varying parameter is derived to reflect the CWSC periodic/abrupt variations under both drought and non-drought periods. Secondly, the change points and varying patterns of the CWSC are analysed based on the Bayesian change point analysis with multiple evaluation criteria. Finally, multiple catchment properties and climate characteristics are used to explore the possible relationship between these variables and the temporal variation characteristic of the CWSC. The catchments suffered from prolonged meteorological drought in southeast Australia are selected as the case study. Results indicate that: (1) the increase of CWSC amplitude change has been observed in 83/92 catchments during the prolonged drought period and the significant shifts in the mean value of the CWSC are detected in 77/92 catchments; (2) the median response time of CWSC for all 92 catchments with significant changes is 641.3 days; (3) the values of CWSC are changed significantly in the catchments with small area\\low elevation\\small slope range\\large forest coverage and high soil water holding capacity. This study might enhance our understanding to the variations in catchment property under different climate-changing patterns.