Dry and wet climate periods over Eastern South America: identification and characterization through the SPEI index

• Published in: Atmosphere
• Main Authors: Drumond, Anita, Stojanovic, Milica, Nieto Muñiz, Raquel Olalla, Gimeno Presa, Luis, Liberato, Margarida L. R., Pauliquevis, Theotonio, Oliveira, Marina, Ambrizzi, Tercio
• Format: Article in Journal/Newspaper
• Language: English
• Published: Atmosphere 2021
• Subjects: 2502 Climatología; 2501.06 Dinámica Atmosférica; 2508.10 Precipitación; South Atlantic Ocean
• Online Access: http://hdl.handle.net/11093/2169; https://doi.org/10.3390/atmos12020155; https://www.mdpi.com/2073-4433/12/2/155

A large part of the population and the economic activities of South America are located in eastern regions of the continent, where extreme climate events are a recurrent phenomenon. This study identifies and characterizes the dry and wet climate periods at domain-scale occurring over the eastern South America (ESA) during 1980–2018 through the multi-scalar Standardized Precipitation–Evapotranspiration Index (SPEI). For this study, the spatial extent of ESA was defined according to a Lagrangian approach for moisture analysis. It consists of the major continental sink of the moisture transported from the South Atlantic Ocean throughout the year, comprising the Amazonia, central Brazil, and the southeastern continental areas. The SPEI for 1, 3, 6, and 12 months of accumulation was calculated using monthly precipitation and potential evapotranspiration time series averaged on ESA. The analysis of the climate periods followed two different approaches: classification of the monthly SPEI values as mild, moderate, severe, and extreme; the computation of the events and their respective parameters (duration, severity, intensity, and peak). The results indicate that wet periods prevailed in the 1990s and 2000s, while dry conditions predominated in the 2010s, when the longest and more severe dry events have been identified at the four scales. Fundação de Amparo à Pesquisa do Estado de São Paulo | Ref. 2020/09548-2 Fundação para a Ciência e a Tecnologia (Portugal) | Ref. UIDB / 50019/2020 – IDL Fundação para a Ciência e a Tecnologia (Portugal) | Ref. PTDC / CTA-MET / 29233/2017 Xunta de Galicia | Ref. ED431C 2017/64-GRC National Institute of Science and Technology for Climate Change | Ref. 465501 / 2014-1 National Institute of Science and Technology for Climate Change | Ref. FAPESP 2014 / 50848-9 National Institute of Science and Technology for Climate Change | Ref. 2017 / 09659-6 National Institute of Science and Technology for Climate Change | Ref. CNPq 304298 / 2014-0 National Institute of Science and Technology for Climate Change | Ref. 420262 / 2018-0