The influence of a prolonged meteorological drought on catchment water storage capacity: a hydrological-model perspective

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.

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

“…The original GR4J model framework proposed by Perrin et al (2003) parameter θ1 and its time-varying characteristics are used to represent the change of real CWSC. It is noted that θ2, θ3 and θ4 are assumed to remain constant, similar settings can be found in many previous studies (Westra et al, 2014;Pan et al, 2020).…”

“…Shen et al (2018) Many previous literatures (McNamara et al, 2011;Melsen et al, 2016;Carrer et al, 2019) influence the mechanism of hydrological response of catchments. Our previous study (Pan et al, 2020) has showed that significant shift in the CWSC has been identified in almost two thirds of the catchments in south-eastern Australia during the prolonged meteorological drought period compared with the previous non-drought period, which may result in the opposite response in two subsets of catchments, i.e., runoff generation rates of some catchments were lower while others had higher runoff generation rate.…”

“…For example, Westra et al (2014) found that the streamflow prediction of the Scott Creek catchment in South Australia was significantly improved if the CWSC is allowed to change over time as a combined function. Pan et al (2020) identified the impact of meteorological drought on CWSC by investigating the changes of hydrological model parameters before and after drought events.…”

Adaptive optimal allocation of water resources response to future water availability and water demand in the Han River basin, China

“…A large number of studies have been presented to assess the hydrological response to climate change or anthropic intervention at different scales with the purpose to formulate adaptive water resources planning and allocation strategies for the future 17 , 19 – 21 . For example, Chawla and Mujumdar 20 examined the runoff response in the upper Ganga basin with the VIC model and illustrated that the runoff is sensitive to the change of urban areas and climate change.…”

“…For example, Chawla and Mujumdar 20 examined the runoff response in the upper Ganga basin with the VIC model and illustrated that the runoff is sensitive to the change of urban areas and climate change. Pan et al 21 studied the hydrological response of 83 catchments in southeastern Australia before and during the meteorological drought period based on the GR4J model, and significant shifts in the catchment water storage capacity have been observed in 62.7% of the meteorological drought period. Yin et al 17 studied the temperature scaling of precipitation and storm runoff extremes under different climate conditions over mainland China.…”