Extreme Rainfall of the South American Monsoon System: A Dataset Comparison Using Complex Networks

Author(s)

Boers, Niklas ^{[1, 2]} ; Bookhagen, Bodo ^[3] ; Marengo, Jose ^[4] ; Marwan, Norbert ^[2] ; von Storch, Jin-Song ^[5] ; Kurths, Juergen ^{[1, 6, 2]}

Affiliation

^[1] Humboldt Univ, Dept Phys, Berlin - Germany

^[2] Potsdam Inst Climate Impact Res, D-14412 Potsdam, Brandenburg - Germany

^[3] Univ Potsdam, Inst Earth & Environm Sci, Potsdam - Germany

^[4] Inst Nacl Pesquisa Espacial, Ctr Ciencia Sistema Terr, Sao Paulo - Brazil

^[5] Max Planck Inst Meteorol, D-20146 Hamburg - Germany

^[6] Nizhnii Novgorod State Univ, Dept Control Theory, Nizhnii Novgorod - Russia

• Document type: Journal article
• Source: Journal of Climate; v. 28, n. 3, p. 1031-1056, FEB 1 2015.
• Web of Science Citations: 19

Abstract

In this study, the authors compare six different rainfall datasets for South America with a focus on their representation of extreme rainfall during the monsoon season (December February): the gauge-calibrated TRMM 3B42 V7 satellite product; the near-real-time TRMM 3B42 V7 RT, the GPCP 1 degrees daily (1DD) V1.2 satellite gauge combination product, the Interim ECMWF Re-Analysis (ERA-Interim) product; output of a high-spatial-resolution run of the ECHAM6 global circulation model; and output of the regional climate model Eta. For the latter three, this study can be understood as a model evaluation. In addition to statistical values of local rainfall distributions, the authors focus on the spatial characteristics of extreme rainfall covariability. Since traditional approaches based on principal component analysis are not applicable in the context of extreme events, they apply and further develop methods based on complex network theory. This way, the authors uncover substantial differences in extreme rainfall patterns between the different datasets: (i) The three model-derived datasets yield very different results than the satellite gauge combinations regarding the main climatological propagation pathways of extreme events as well as the main convergence zones of the monsoon system. (ii) Large discrepancies are found for the development of mesoscale convective systems in southeastern South America. (iii) Both TRMM datasets and ECHAM6 indicate a linkage of extreme rainfall events between the central Amazon basin and the eastern slopes of the central Andes, but this pattern is not reproduced by the remaining datasets. The authors' study suggests that none of the three model-derived datasets adequately captures extreme rainfall patterns in South America. (AU)

• FAPESP's process: 13/50538-7 - Understanding the causes of the biases that determine the onset of the rainy season in Amazonia in climate models using GoAmazon-CHUVA measurements
• Grantee: Jose Antonio Marengo Orsini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/50151-0 - Dynamical phenomena in complex networks: fundamentals and applications
• Grantee: Elbert Einstein Nehrer Macau
• Support Opportunities: Research Projects - Thematic Grants