Title
Changes in Normalized Difference Vegetation Index in the Orinoco and Amazon River Basins: Links to Tropical Atlantic Surface Temperatures
Date Issued
01 October 2020
Access level
open access
Resource Type
journal article
Author(s)
Publisher(s)
American Meteorological Society
Abstract
We analyze the observed relationship between sea surface temperatures (SSTs) over the Atlantic Ocean and the normalized difference vegetation index (NDVI) in the Orinoco and Amazon basins. Monthly correlations between anomalies of NDVI and SSTs are computed for different regions of the Atlantic Ocean. We also use a mixture of observations and reanalysis products to analyze lagged correlations. Our results show that during August–September (i.e., the dry-to-wet transition season), changes in NDVI in the central Amazon and the so-called Arc of Deforestation are associated with precedent changes in the SSTs of the tropical North Atlantic (TNA) and the Caribbean (CABN) during March–June. Anomalous warming of the CABN and TNA generates changes in surface winds and atmospheric moisture transport in the region, decreasing precipitation, with consequent decreases of soil moisture, moisture recycling, and NDVI. An increase in TNA and CABN SSTs during March–June is also associated with an increase of NDVI over the northern Orinoco during June (i.e., the wet season). Unlike in the southern Amazon, precipitation and soil moisture in the Orinoco basin do not exhibit significant changes associated with SSTs. By contrast, atmospheric moisture recycling and transport increase with warmer SSTs in the TNA. Therefore, for the Orinoco, the link between SSTs and NDVI appears to be related not to changes in precipitation but to changes in moisture recycling. However, the causality between these changes needs to be further explored. These findings highlight the contrasting responses of the Amazon and Orinoco basins to Atlantic temperatures and the dominant role of atmospheric moisture transport linking these responses.
Start page
8537
End page
8559
Volume
33
Issue
19
Language
English
OCDE Knowledge area
Meteorología y ciencias atmosféricas
Oceanografía, Hidrología, Recursos hídricos
Subjects
Scopus EID
2-s2.0-85095773644
Source
Journal of Climate
ISSN of the container
08948755
Sponsor(s)
Acknowledgments. This work was founded by Universidad de Antioquia through the Grant CODI PRG2017-16264. J. C. Espinoza and S. Wongchuig-Correa were supported by the AMANECER (Amazon-Andes Connectivity) Project–Make Our Planet Great Again Program, funded by ANR and IRD (ANR-18-MPGA-0008). We acknowledge Melissa Ruiz-Vásquez for providing Fig. 1. We are also thankful for the insightful comments from three anonymous reviewers and the Editor. The authors indicate no conflict of interests.
Sources of information:
Directorio de Producción Científica
Scopus