Changes in summer precipitation variability in central Brazil over the past eight decades

Author(s)

Prado, Luciana Figueiredo ^{[1, 2]} ; Wainer, Ilana ^[1] ; Yokoyama, Elder ^[2] ; Khodri, Myriam ^{[3, 4]} ; Garnier, Jeremie ^[2]

Affiliation

^[1] Univ Sao Paulo, Oceanog Inst, Praca Oceanog 191, Cidade Univ, BR-05508120 Sao Paulo - Brazil

^[2] Univ Brasilia, ICC Cent, Inst Geosci, Campus Darcy Ribeiro, Brasilia, DF - Brazil

^[3] Inst Pierre Simon Laplace, LOCEAN, Paris - France

^[4] Univ Paris 06, CNRS, IRD, Paris - France

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF CLIMATOLOGY; v. 41, n. 8, p. 4171-4186, JUN 30 2021.
• Web of Science Citations: 1

Abstract

Central Brazil hydroclimate is in the core region of the South American monsoon system. Thus, understanding precipitation variability in this area is crucial not only for the prediction of extreme events such as droughts and floods, but also for water resources management. Ocean teleconnections influence central Brazil precipitation from intraseasonal to interdecadal frequencies, in both linear and nonlinear ways, mainly during the austral summer. Pacific Ocean climate modes can influence South American precipitation, but how its variability changes over time is still a theme of scientific debate. Here we examined the influence of Pacific variability on summer precipitation in central Brazil during the last eight decades. We applied nonparametric spectral methods to four different observational datasets, and to AMIP-type precipitation outputs from the Laboratoire de Meteorologie Dynamique zoom model (LMDZ) in Coupled Model Intercomparison Project phases 5 and 6 (CMIP5 and CMIP6) contributions of the Institut Pierre Simon Laplace (IPSL) coupled model. Our results showed an increase in amplitude and frequency of summer precipitation variability after the 1970s climate transition. Spectral analysis associated these changes to a transition in Pacific Ocean influence to central Brazil precipitation, from PDO- to El Nino-Southern Oscillation (ENSO)-related variability after the 1970s climate transition. Composite analysis suggests these changes are related to teleconnection patterns between the Pacific Ocean and South America precipitation. (AU)

• FAPESP's process: 15/50686-1 - Paleo-constraints on monsoon evolution and dynamics
• Grantee: Pedro Leite da Silva Dias
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/14789-9 - Impact of volcanism on the South American Monsoon System and its relationship with the Atlantic Ocean sea surface temperature modes of variability
• Grantee: Ilana Elazari Klein Coaracy Wainer
• Support Opportunities: Regular Research Grants