Minimum Rainfall Inter-Event Time to Separate Rainfall Events in a Low Latitude Semi-Arid Environment

Sustainability

Jacques Carvalho Ribeiro Filho¹  José Bandeira Brasil¹  Eunice Maia de Andrade²  Maria Simas Guerreiro³  Helba Araújo de Queiroz Palácio⁴  Pedro Henrique Augusto Medeiros⁴ 

[1] Department of Agricultural Engineering, Federal University of Ceará–UFC, Fortaleza 60020-181, Brazil;Department of Soil and Water Conservation, Federal University of the Semi-Arid Region, Mossoró 59625-900, Brazil;FP-ENAS, University Fernando Pessoa, 4249-004 Porto, Portugal;Federal Institute of Education, Science and Technology of Ceará, Iguatu 63500-000, Brazil;

关键词: rainfall characteristics;    rain events separation;    tropical dry regions;    hydrological processes;   

DOI  :  10.3390/su14031721

来源: DOAJ

【 摘 要 】

Water scarcity in dry tropical regions is expected to intensify due to climate change. Characterization of rainfall events is needed for a better assessment of the associated hydrological processes, and the proposition of adaptation strategies. There is still no consensus on the most appropriate method to separate rainfall events from a continuous database, although the minimum inter-event time (MIET) is a commonly used criterion. Semi-arid regions of low latitudes hold a distinct rainfall pattern compared to their equivalent at higher latitudes; these seasonally dry tropical forests experience strong spatial–temporal variability with intense short-duration rainfall events, which, in association with high energy surplus and potential evaporation, leads to an atmospheric water deficit. In this study, we identified the most adequate MIET based on rainfall data continuously measured at 5-min intervals over the last decade (2009–2020) in the semi-arid northeast of Brazil. The rainfall events were grouped according to different MIETs: 15 min, 1 h, 2 h, 3 h, 6 h, 12 h, and 24 h to determine rainfall depth, duration and intensity at intervals of 5, 30, and 60 min, time between events, and respective temporal distribution, with and without single tip events. Including single tip events in the dataset affected the number of rainfall events and respective characteristics up to a MIET of 3 h. A MIET of 6 h is the most appropriate to characterize the rainfall distribution in this tropical semi-arid region. Three classes were defined based on rainfall depth, duration, and intensity: I-small events (77% below 40 mm and 32 mm/h), II-high intensity events (3% between 36 and 76 mm/h), III-longer events of higher depth (20%). This study is useful for understanding how the MIET relates to other ecohydrological processes and provides more precise information on the rainfall characteristics at the event scale.

【 授权许可】

Unknown