Underestimated role of East Atlantic-West Russia pattern on Amazon vegetation productivity

The Amazon forest experienced severe droughts in 2005 and 2010; however, the extent to which precipitation anomaly affects the vegetation productivity remains controversial (1, 2). Hilker et al. (3) report significant correlations (P < 0.05) between the El Nino southern oscillation (ENSO) and the Amazon vegetation greenness based on the improved moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) data for 2000–2012. The opposing findings from previous MODIS measurements are attributed to normalizing the MODIS reflectance to a common view and sun geometry and the use of a less conservative cloud mask. These are important developments, particularly to study the intraannual dynamics of Amazon vegetation greenness. However, we argue that, among the leading global ocean-atmosphere oscillations, ENSO may not be the most prominent indicator of Amazon vegetation productivity.