Temporal evolution of the spatial covariability of rainfall in South America

Catrin Ciemer*, Niklas Boers, Henrique M. J. Barbosa, Jurgen Kurths, Anja Rammig

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The climate of South America exhibits pronounced differences between rainy and dry seasons, associated with specific synoptic features such as the establishment of the South Atlantic convergence zone. Here, we analyze the spatiotemporal correlation structure and in particular teleconnections of daily rainfall associated with these features by means of evolving complex networks. A modification of Pearson's correlation coefficient is introduced to handle the intricate statistical properties of daily rainfall. On this basis, spatial correlation networks are constructed, and new appropriate network measures are introduced in order to analyze the temporal evolution of the networks' characteristics. We particularly focus on the identification of coherent areas of similar rainfall patterns and previously unknown teleconnection structures between remote areas. We show that the monsoon onset is characterized by an abrupt transition from erratic to organized regional connectivity that prevails during the monsoon season, while only the onset times themselves exhibit anomalous large-scale organization of teleconnections. Furthermore, we reveal that the two mega-droughts in the Amazon basin were already announced in the previous year by an anomalous behavior of the connectivity structure.

Original languageEnglish
Pages (from-to)371-382
Number of pages12
JournalClimate dynamics
Volume51
Issue number1-2
Early online date6 Oct 2017
DOIs
Publication statusPublished - 31 Jul 2018

Keywords

  • South American monsoon
  • Complex networks
  • Rainfall
  • Teleconnections
  • Correlation measures
  • LOW-LEVEL JET
  • COMPLEX NETWORKS
  • MONSOON SYSTEM
  • VARIABILITY
  • CLIMATE
  • CONVECTION
  • DROUGHT
  • FRONTS

Cite this

Ciemer, C., Boers, N., Barbosa, H. M. J., Kurths, J., & Rammig, A. (2018). Temporal evolution of the spatial covariability of rainfall in South America. Climate dynamics, 51(1-2), 371-382. https://doi.org/10.1007/s00382-017-3929-x