Developing objective dry spell and drought triggers for drought monitoring in the Niger Basin of West Africa

J. N. Okpara (), K. O. Ogunjobi and E. A. Adefisan
Additional contact information
J. N. Okpara: Federal University of Technology, Akure (FUTA)
K. O. Ogunjobi: Federal University of Technology, Akure (FUTA)
E. A. Adefisan: Federal University of Technology, Akure (FUTA)

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards, 2022, vol. 112, issue 3, No 25, 2465-2492

Abstract: Abstract To effectively manage drought in the Niger River Basin known for its high interannual rainfall variability and continuous adverse drought impacts and challenges, decision-makers need to distinguish dry spells from drought. Operational drought triggers also needed to activate water resource management measures and determine the level of intervention, which are presently lacking. With 36 years of precipitation reanalysis records from 60 locations, the study attempts to establish index- and percentiles-based thresholds for defining dry spell and drought through baseline assessment analysis of the historic 1980s regional drought-induced famine, using percentile rank approach. Results indicate 1980s drought-induced famine occurred within thresholds of 20th, 10th, 5th, and 2nd percentiles, while the drought precursors, the dry spells occur within 35th, 20th, 10th, and 5th percentiles. The corresponding objective index thresholds based on SPI-2 month ranges from − 0.22 to − 0.45, − 0.45 to − 0.93, − 0.93 to − 1.20, − 1.66 to − 1.83 defining dry spell, abnormal dry spell, critical/extreme dry spell, and drought conditions; and SPI-6 month thresholds of range − 0.38 to − 1.07, − 0.59 to − 1.58, − 0.64 to − 1.79 and − 0.67 to − 2.21 defining drought of moderate, severe, extreme, and exceptional intensities respectively depending on location. The thresholds vary from month to month, reflecting seasonality, and detect drought onset much earlier because of its lower values relative to the higher, subjective, and arbitrary fixed SPI thresholds of − 1.0 to − 1.49 for defining moderate drought conditions that could be misleading. The threshold validation results show a success rate of 50 to 70 percent. Results operationally useful for early drought detection.

Keywords: Drought; Definition; SPI; Reanalysis; Percentile; Niger basin (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
http://link.springer.com/10.1007/s11069-022-05273-3 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:nathaz:v:112:y:2022:i:3:d:10.1007_s11069-022-05273-3

Ordering information: This journal article can be ordered from
http://www.springer.com/economics/journal/11069

DOI: 10.1007/s11069-022-05273-3

Access Statistics for this article

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards is currently edited by Thomas Glade, Tad S. Murty and Vladimír Schenk

More articles in Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards from Springer, International Society for the Prevention and Mitigation of Natural Hazards
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().