Soil moisture and streamflow deficit anomaly index: an approach to quantify drought hazards by combining deficit and anomaly
Open Access
- 3 May 2021
- journal article
- research article
- Published by Copernicus GmbH in Natural Hazards and Earth System Sciences
- Vol. 21 (5), 1337-1354
- https://doi.org/10.5194/nhess-21-1337-2021
Abstract
Drought is understood as both a lack of water (i.e., a deficit compared to demand) and a temporal anomaly in one or more components of the hydrological cycle. Most drought indices, however, only consider the anomaly aspect, i.e., how unusual the condition is. In this paper, we present two drought hazard indices that reflect both the deficit and anomaly aspects. The soil moisture deficit anomaly index, SMDAI, is based on the drought severity index, DSI (Cammalleri et al., 2016), but is computed in a more straightforward way that does not require the definition of a mapping function. We propose a new indicator of drought hazard for water supply from rivers, the streamflow deficit anomaly index, QDAI, which takes into account the surface water demand of humans and freshwater biota. Both indices are computed and analyzed at the global scale, with a spatial resolution of roughly 50 km, for the period 1981–2010, using monthly time series of variables computed by the global water resources and the model WaterGAP 2.2d. We found that the SMDAI and QDAI values are broadly similar to values of purely anomaly-based indices. However, the deficit anomaly indices provide more differentiated spatial and temporal patterns that help to distinguish the degree and nature of the actual drought hazard to vegetation health or the water supply. QDAI can be made relevant for stakeholders with different perceptions about the importance of ecosystem protection, by adapting the approach for computing the amount of water that is required to remain in the river for the well-being of the river ecosystem. Both deficit anomaly indices are well suited for inclusion in local or global drought risk studies.This publication has 36 references indexed in Scilit:
- A PRESUMPTIVE STANDARD FOR ENVIRONMENTAL FLOW PROTECTIONRiver Research and Applications, 2011
- The impact of droughts and water management on various hydrological systems in the headwaters of the Tagus River (central Spain)Journal of Hydrology, 2010
- A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration IndexJournal of Climate, 2010
- On the use of Standardized Precipitation Index (SPI) for drought intensity assessmentMeteorlogical Applications, 2009
- Development of the Soil Moisture Index to Quantify Agricultural Drought and Its “User Friendliness” in Severity-Area-Duration AssessmentJournal of Hydrometeorology, 2008
- Value of river discharge data for global-scale hydrological modelingHydrology and Earth System Sciences, 2008
- A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface WarmingJournal of Hydrometeorology, 2004
- Development and testing of the WaterGAP 2 global model of water use and availabilityHydrological Sciences Journal, 2003
- A global hydrological model for deriving water availability indicators: model tuning and validationJournal of Hydrology, 2003
- An evaluation of the Standardized Precipitation Index, the China‐Z Index and the statistical Z‐ScoreInternational Journal of Climatology, 2001