Title
Empirical–statistical downscaling of austral summer precipitation over south america, with a focus on the central peruvian andes and the equatorial amazon basin
Date Issued
01 January 2020
Access level
open access
Resource Type
journal article
Publisher(s)
American Meteorological Society
Abstract
Precipitation is one of the most difficult variables to estimate using large-scale predictors. Over South America (SA), this task is even more challenging, given the complex topography of the Andes. Empirical–statistical downscaling (ESD) models can be used for this purpose, but such models, applicable for all of SA, have not yet been developed. To address this issue, we construct an ESD model using multiple-linear-regression techniques for the period 1982–2016 that is based on large-scale circulation indices representing tropical Pacific Ocean, Atlantic Ocean, and South American climate variability, to estimate austral summer [December–February (DJF)] precipitation over SA. Statistical analyses show that the ESD model can reproduce observed precipitation anomalies over the tropical Andes (Ecuador, Colombia, Peru, and Bolivia), the eastern equatorial Amazon basin, and the central part of the western Argentinian Andes. On a smaller scale, the ESD model also shows good results over the Western Cordillera of the Peruvian Andes. The ESD model reproduces anomalously dry conditions over the eastern equatorial Amazon and the wet conditions over southeastern South America (SESA) during the three extreme El Niños: 1982/83, 1997/98, and 2015/16. However, it overestimates the observed intensities over SESA. For the central Peruvian Andes as a case study, results further show that the ESD model can correctly reproduce DJF precipitation anomalies over the entire Mantaro basin during the three extreme El Niño episodes. Moreover, multiple experiments with varying predictor combinations of the ESD model cor-roborate the hypothesis that the interaction between the South Atlantic convergence zone and the equatorial Atlantic Ocean provoked the Amazon drought in 2015/16.
Start page
65
End page
85
Volume
60
Issue
1
Language
English
OCDE Knowledge area
Ingeniería oceanográfica Oceanografía, Hidrología, Recursos hídricos Meteorología y ciencias atmosféricas
Scopus EID
2-s2.0-85100664584
Source
Journal of Applied Meteorology and Climatology
ISSN of the container
15588424
Sponsor(s)
Acknowledgments. The authors thank the PPR 068 ‘‘Reducción de vulnerabilidad y atención de emergencias por desastres’’ program. The authors also thank Dr. Takahashi for useful discussions during the initial part of this study. Moreover, the authors thank Ing. Prudencio for his help with the production of some figures. The authors also thank Dr. Lavado-Casimiro and his group (Cesar Aybar and Fiorella Vega) for providing the PISCO data. The authors also thank the project ‘‘MAGNET-IGP: Strengthening the research line in physics and microphysics of the atmosphere (Agreement 010-2017-FONDECYT),’’ financed by the Consejo Nacional de Ciencia y Tecnología (CONCYTEC), Peru. We are very grateful to three anonymous reviewers who provided us with valuable comments, which helped us to advance our results significantly and to improve the paper. Author M. Vuille was partially supported by NSF-PIRE (OISE-1743738) and NSF-P2C2 (AGS-1702439). This work was performed using computational resources, HPC-Linux-Cluster, from the Laboratorio de Dinámica de Fluidos Geofísicos Computacionales (http://scah.igp.gob.pe/laboratorios/dfgc) at the Instituto Geofísico del Perú (Grant 101-2014-FONDECYT).
Sources of information: Directorio de Producción Científica Scopus