Hydrological Drought Instantaneous Propagation Speed Based on the Variable Motion Relationship of Speed‐Time Process

Abstract

It is difficult to predict and track the propagation of a hydrological drought because it is hard to determine its propagation speed. We propose a useful framework for calculating the hydrological drought instantaneous propagation speed which includes the instantaneous development speed (IDS) and instantaneous recovery speed (IRS). First, the run theory was applied to subdivide the propagation of individual hydrological drought events into the development and recovery stages and to determine the individual propagation times (drought development duration and drought recovery duration). Then the hydrological drought instantaneous propagation speed of each hydrological drought event, including the IDS and IRS, were determined based on the variable motion relationship of speed‐time process commonly applied in physics. Finally, the optimal theoretical values of the IDS and IRS were evaluated using a cross‐validation method. Three hydrometric stations, located at the upstream catchment with less human activities influence, were chosen from different countries (China, the United States, and Germany) to demonstrate the satisfactory performance of this proposed framework. The results indicate that the variable motion relationship of speed‐time process can provide an assessment of the overall hydrological drought propagation and perform well for identifying the propagation time in these study areas. The optimal theoretical values of IDS (or IRS) obtained by the variable motion relationship can simulate the actual drought development duration (or drought recovery duration) of hydrological drought well. The sensitivity of IDS (or IRS) of hydrological drought is correlated with climate, catchment characteristics, and human activities that should be explored to improve hydrological drought propagation prediction.

Propagation of Meteorological to Hydrological Droughts in India

“…The information about the internal propagation, the development, and recovery of hydrological drought at the sub‐basin scale can help water managers in developing efficient water management strategies at the sub‐basin level. We used the framework suggested by Wu et al (2018) to estimate the IDS and IRS for the hydrological droughts identified during the 1901–2012 period at the 223 locations in the Indian subcontinental river basins. We compared the optimal IDS estimated using the observed and VIC model‐simulated 1‐month SSI at eight observed stations located in eight different basins (Table S2), to evaluate its applicability to 223 sub‐basins.…”

“…The cross‐validation method was used to test the performance of a predictive model with an independent data set, which is not used in model development (Hu & Bentler, 1999). For the detailed description of the cross‐validation method, please refer to Wu et al (2018). Once the optimal values of IDS (IRS) using the cross‐validation method were estimated, we back predicted drought development/recovery durations (DDD pre /DRD pre ) based on optimal IDS (IRS) and TVDP (TVRP) using Equation () for all the drought events (Figure S3).…”

“…Drought propagation refers to the growth of deficits and its recovery at the end of a drought spell (Parry et al, 2016(Parry et al, , 2018Wu et al, 2018). Previous studies investigated the development and recovery phases and associated propagation rates as characteristics of hydrological droughts (Parry et al, 2016;Thomas et al, 2014).…”

A 35-year meteorological drought analysis in the Caribbean Region: case study of the small island state of Trinidad and Tobago

“…These categories are meteorological, hydrological, agricultural or socioeconomic droughts. A meteorological drought describes a time period with a below average rainfall; hydrological droughts occur when there is a deficit in rainfall which affects the sub-surface moisture, surface water reservoirs and ground water; while agriculture droughts are classified when the soil moisture is low and has a negative impact on crops; and a socioeconomic drought occurs when a commodity is affected by drought conditions and there is insufficient product to meet the demand [52,53].…”

Multivariate Assessment of Low-Flow Hazards via Copulas: The Case Study of the Çoruh Basin (Turkey)

“…Different drought definitions are proposed in literature, and droughts are generally classified in four types: meteorological, hydrological, agricultural and socio-economic [2]. Hydrological droughts (entailing a significant reduction of available surface and subsurface water variables, such as river streamflow, groundwater, reservoir and lake levels), are considered as having the most serious impacts on water supply [3,4]. In particular, the streamflows are considered as important indicators that define the status of surface water resources [5].…”