Abstract
Abstract. Building on almost 10 years of expertise and operational application of the Combined Drought Indicator (CDI), which is implemented within the European Commission's European Drought Observatory (EDO) for the purposes of early warning and monitoring of agricultural droughts in Europe, this paper proposes a revised version of the index. The CDI conceptualizes drought as a cascade process, where a precipitation shortage (WATCH stage) develops into a soil water deficit (WARNING stage), which in turn leads to stress for vegetation (ALERT stage). The main goal of the revised CDI proposed here is to improve the indicator's performance for those events that are currently not reliably represented, without altering either the modelling conceptual framework or the required input datasets. This is achieved by means of two main modifications: (a) use of the previously occurring CDI value to improve the temporal consistency of the time series and (b) introduction of two temporary classes – namely TEMPORARY RECOVERY for soil moisture and vegetation greenness, respectively – to avoid brief discontinuities in a stage. The efficacy of the modifications is tested by comparing the performances of the revised and currently implemented versions of the indicator for actual drought events in Europe during the last 20 years. The revised CDI reliably reproduces the evolution of major droughts, outperforming the current version of the indicator, especially for long-lasting events, and reducing the overall temporal inconsistencies in stage sequencing of about 70 %. Since the revised CDI does not need supplementary input datasets, it is suitable for operational implementation within the EDO drought monitoring system.
Highlights
In the past 20 years, the monitoring of drought events has gained increasing relevance thanks to the shift in the paradigm for drought risk management from a reactive to a proactive approach (Wilhite and Pulwarty, 2005)
One of the main improvements that may be expected in the revised version of the Combined Drought Indicator (CDI) (CDI-v2) concerns the temporal consistency at the local scale
An initial test was made to compare the temporal behaviour of the current version (CDI-v1) and proposed revision (CDI-v2) of the indicator, over selected locations in Europe, during well-documented drought events
Summary
In the past 20 years, the monitoring of drought events has gained increasing relevance thanks to the shift in the paradigm for drought risk management from a reactive to a proactive approach (Wilhite and Pulwarty, 2005). As advocated by WMO and GWP (2014), drought monitoring and early warning systems represent one of the three main pillars for successful integrated drought management (the others being vulnerability and impact assessment and drought preparedness, mitigation, and response). A drought monitoring and early warning system identifies climate and water resources trends and detects the emergence or probability of occurrence and the likely severity of droughts and its impacts, and it should provide reliable information about impending drought conditions that can be timely communicated to water managers, policymakers, and the public (Vogt et al, 2018a). The authors distinguish among three typologies of index-based monitoring systems: (i) single indicator, (ii) multiple indicators, and (iii) composite or hybrid indicators. The latter group allows for the in-
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
