Evapotranspiration trends and variability in southeastern South America: The roles of land-cover change and precipitation variability

Author(s):Show less -

Ruscica, Romina C. ^{[1, 2, 3]} ; Sorensson, Anna A. ^{[1, 2, 3]} ; Diaz, Leandro B. ^{[1, 2, 3]} ; Vera, Carolina ^{[1, 2, 3]} ; Castro, Aline ^[4] ; Papastefanou, Phillip ^[5] ; Rammig, Anja ^[5] ; Rezende, Luiz F. C. ^[4] ; Sakschewski, Boris ^[6] ; Thonicke, Kirsten ^[6] ; Viovy, Nicolas ^[7] ; von Randow, Celso ^[4]

Affiliation

^[1] Univ Buenos Aires, Fac Ciencias Exactas & Nat, Dept Ciencias Atmosfera & Oceanos, Buenos Aires, DF - Argentina

^[2] Univ Buenos Aires, CONICET, Ctr Invest Mar & Atmosfera CIMA, Buenos Aires, DF - Argentina

^[3] UBA, CONICET, Inst Franco Argentino Estudio Clima & Impactos UM, CNRS, IRD, Buenos Aires, DF - Argentina

^[4] Natl Inst Space Res INPE, Impacts Adaptat & Vulnerabil Div, Sao Jose Dos Campos, SP - Brazil

^[5] Tech Univ Munich, TUM Sch Life Sci, Freising Weihenstephan - Germany

^[6] Leibniz Assoc, Potsdam Inst Climate Impact Res PIK, Potsdam - Germany

^[7] Univ Paris Saclay, CNRS, Lab Sci Climat & Environm LSCE, CEA, UVSQ, Gif Sur Yvette - France

• Document type: Journal article
• Source: INTERNATIONAL JOURNAL OF CLIMATOLOGY; SEP 2021.
• Web of Science Citations: 0

Abstract

Southeastern South America is subject to considerable precipitation variability on seasonal to decadal timescales and has undergone very heavy land-cover changes (LCCs) since the middle of the past century. The influence of local LCC and precipitation as drivers of regional evapotranspiration (ET) long-term trends and variability remains largely unknown in the region. Here, ensembles of stand-alone dynamic global vegetation models (DGVMs) with different atmospheric forcings are used to disentangle the influence of those two drivers on austral summer ET from 1950 to 2010. This paper examines the influence of both the El Nino-Southern Oscillation (ENSO) and the dipole-like first-mode of southeastern South American precipitation variability (EOF1) on regional ET. We found that in the lower La Plata Basin, ET was driven by precipitation variability and showed a positive summer trend. Moreover, the region showed marked seasonal anomalies during El Nino and La Nina summers but mainly during EOF1 phases. On the contrary, in the upper La Plata Basin, LCCs forced the negative summer ET trend and particularly reduced the summer anomalies of the late 1990s, a period of ENSO and EOF1-positive phases. In the South Atlantic Convergence Zone region, the high ET uncertainty across ensemble members impeded finding robust results, which highlights the importance of using multiple DGVMs and atmospheric forcings instead of relying on single model/forcing results. (AU)

• FAPESP's process: 15/50687-8 - Climate services through knowledge co-production: a Euro-South American initiative for strengthening societal adaptation response to extreme events
• Grantee: Iracema Fonseca de Albuquerque Cavalcanti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/03048-5 - Simulations of forest disturbances and land use change in the Amazon and possible impacts on the regional climate and rainfall in southeastern South America
• Grantee: Luiz Felipe Campos de Rezende
• Support Opportunities: Scholarships in Brazil - Post-Doctoral