Abstract
Drought periods appear as extreme events whose characterization encompasses several issues. Many issues are related to the multiple natures that a drought may have: meteorological, hydrological, agricultural, or socioeconomical. There are also issues related to the complexity of the phenomena, which may be characterized by many magnitudes, such as duration, severity, or intensity. None of them alone may be used as a general drought characterization criterion. Others arise from the kind of methodologies that are available for their significance evaluation, which focus on different aspects for specific objectives. However, most have a common aspect: the extreme persistent realization of a random hydroclimatic variable. For the goal of general drought analysis, in this paper a new index for drought characterization is presented: the drought frequency index (DFI). The index focuses on this common aspect of the drought origins, with a purely probabilistic treatment. Because droughts are persistent phenomena, the index is based on the stochastic characterization of extreme persistent deviation sequences using a novel probabilistic criterion. In this way, the DFI is related to the mean frequency of recurrence of extreme persistent events. Therefore the mean frequency of recurrence is adopted as the scale for drought significance evaluation. The index performance is analyzed and compared with respect to the different issues that result from applying other methodologies: magnitude selection, univariate versus multivariate, threshold selection (related to the run theory), and timescale issues (related with the standard precipitation index (SPI) application). Furthermore, to apply runs theory for any magnitude number, an original generalization of drought multivariate recurrence models is presented. Finally, the spatial comparability of the indexes is analyzed. Results reveal the ability of the DFI to reduce the sensitivity to practical issues. The DFI provides a consistent index for spatial comparisons and for application to general drought characterization goals.
Keywords
UnivariateMultivariate statisticsProbabilistic logicIndex (typography)Standard deviationStatisticsMathematicsSelection (genetic algorithm)ClimatologyEconometricsEnvironmental scienceComputer scienceGeologyArtificial intelligence
Affiliated Institutions
Related Publications
Histopathologic-Based Prognostic Factors of Colorectal Cancers Are Associated With the State of the Local Immune Reaction
Purpose The prognosis of patients with colorectal cancer has sometimes proved uncertain; thus, the prognostic significance of immune criteria was compared with that of the tumor...
Goodness-of-Fit Testing for Latent Class Models
Latent class models with sparse contingency tables can present problems for model comparison and selection, because under these conditions the distributions of goodness-of-fit i...
Choosing a multivariate model: Noncentrality and goodness of fit.
It is suggested that Akaike's information criterion cannot be used for model selection in real applications and that there are problems attending the definition of parsimonious ...
Gold Nanorods: Electrochemical Synthesis and Optical Properties
Aqueous solutions containing a high yield of suspended gold nanorods have been successfully synthesized via an electrochemical method. The control of preparing gold nanorods wit...
Model-Based Clustering, Discriminant Analysis, and Density Estimation
Cluster analysis is the automated search for groups of related observations in a dataset. Most clustering done in practice is based largely on heuristic but intuitively reasonab...
Publication Info
- Year
- 2006
- Type
- article
- Volume
- 42
- Issue
- 11
- Citations
- 75
- Access
- Closed
External Links
Social Impact
Altmetric
PlumX Metrics
Social media, news, blog, policy document mentions
Citation Metrics
75
OpenAlex
Cite This
Javier González,
Juan B. Valdés
(2006).
New drought frequency index: Definition and comparative performance analysis.
Water Resources Research
, 42
(11)
.
https://doi.org/10.1029/2005wr004308
Identifiers
- DOI
- 10.1029/2005wr004308