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.