How do we identify flash droughts? A case study in Central European Croplands
Many definitions and delineation methods exist for identifying flash droughts (FDs), which are events of rapid and unusual large depletion of root-zone soil moisture, in comparison to average moisture conditions, due to climatic compound conditions over a short period of several weeks. Six FD identi...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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IWA Publishing
2022-09-01
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| Series: | Hydrology Research |
| Subjects: | |
| Online Access: | http://hr.iwaponline.com/content/53/9/1150 |
| _version_ | 1797995619575398400 |
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| author | Pedro Henrique Lima Alencar Eva Nora Paton |
| author_facet | Pedro Henrique Lima Alencar Eva Nora Paton |
| author_sort | Pedro Henrique Lima Alencar |
| collection | DOAJ |
| description | Many definitions and delineation methods exist for identifying flash droughts (FDs), which are events of rapid and unusual large depletion of root-zone soil moisture, in comparison to average moisture conditions, due to climatic compound conditions over a short period of several weeks. Six FD identification methods were compared to analyse their functioning using data from several experimental cropland sites across Central Europe. Co- and misidentification of the FD time series were assessed using confusion and synchronicity metrics on a local scale. Even though a large degree of synchronicity of individual FD events was observed, some divergence in drought periods was detected, which was related to four intrinsic differences in the underlying FD definitions: (1) type of critical variable; (2) velocity of drought intensification; (3) pre-set threshold values for final depletion and/or (4) minimum length of the duration of FDs. To balance the strengths and weaknesses of those methods that are not based on soil moisture, we suggest using an ensemble approach for event identification, which is validated in this study for the temperate central European region. In doing so, the current unclearly defined sub-types of FDs can be detected, regardless of the different combinations of compound drivers and differences in intensification dynamics. All methods were implemented in an R package and are available as a Shiny app for the public.
HIGHLIGHTS
The multiple methods proposed to identify flash droughts (FDs) show substantial disagreement.;
Soil moisture is the key variable to identify FDs in croplands; however, such data are scarce, and a method based on proxy variables is necessary.;
A multi-index or multi-method should be favoured in identifying FDs, as a single proxy (to soil moisture) may cause significant misidentification.; |
| first_indexed | 2024-04-11T10:04:31Z |
| format | Article |
| id | doaj.art-ee51f579eea94dbe8e2e251a7ef94260 |
| institution | Directory Open Access Journal |
| issn | 1998-9563 2224-7955 |
| language | English |
| last_indexed | 2024-04-11T10:04:31Z |
| publishDate | 2022-09-01 |
| publisher | IWA Publishing |
| record_format | Article |
| series | Hydrology Research |
| spelling | doaj.art-ee51f579eea94dbe8e2e251a7ef942602022-12-22T04:30:17ZengIWA PublishingHydrology Research1998-95632224-79552022-09-015391150116510.2166/nh.2022.003003How do we identify flash droughts? A case study in Central European CroplandsPedro Henrique Lima Alencar0Eva Nora Paton1 Ecohydrology and Landscape Evaluation, Institute of Ecology, Technical University of Berlin, Berlin, Germany Ecohydrology and Landscape Evaluation, Institute of Ecology, Technical University of Berlin, Berlin, Germany Many definitions and delineation methods exist for identifying flash droughts (FDs), which are events of rapid and unusual large depletion of root-zone soil moisture, in comparison to average moisture conditions, due to climatic compound conditions over a short period of several weeks. Six FD identification methods were compared to analyse their functioning using data from several experimental cropland sites across Central Europe. Co- and misidentification of the FD time series were assessed using confusion and synchronicity metrics on a local scale. Even though a large degree of synchronicity of individual FD events was observed, some divergence in drought periods was detected, which was related to four intrinsic differences in the underlying FD definitions: (1) type of critical variable; (2) velocity of drought intensification; (3) pre-set threshold values for final depletion and/or (4) minimum length of the duration of FDs. To balance the strengths and weaknesses of those methods that are not based on soil moisture, we suggest using an ensemble approach for event identification, which is validated in this study for the temperate central European region. In doing so, the current unclearly defined sub-types of FDs can be detected, regardless of the different combinations of compound drivers and differences in intensification dynamics. All methods were implemented in an R package and are available as a Shiny app for the public. HIGHLIGHTS The multiple methods proposed to identify flash droughts (FDs) show substantial disagreement.; Soil moisture is the key variable to identify FDs in croplands; however, such data are scarce, and a method based on proxy variables is necessary.; A multi-index or multi-method should be favoured in identifying FDs, as a single proxy (to soil moisture) may cause significant misidentification.;http://hr.iwaponline.com/content/53/9/1150climatic compound eventsconfusion matrixevent identificationflash droughtsynchronicity metrics |
| spellingShingle | Pedro Henrique Lima Alencar Eva Nora Paton How do we identify flash droughts? A case study in Central European Croplands Hydrology Research climatic compound events confusion matrix event identification flash drought synchronicity metrics |
| title | How do we identify flash droughts? A case study in Central European Croplands |
| title_full | How do we identify flash droughts? A case study in Central European Croplands |
| title_fullStr | How do we identify flash droughts? A case study in Central European Croplands |
| title_full_unstemmed | How do we identify flash droughts? A case study in Central European Croplands |
| title_short | How do we identify flash droughts? A case study in Central European Croplands |
| title_sort | how do we identify flash droughts a case study in central european croplands |
| topic | climatic compound events confusion matrix event identification flash drought synchronicity metrics |
| url | http://hr.iwaponline.com/content/53/9/1150 |
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