Spatial and temporal patterns of the recent warming of the Amazon forest

In recent years, several studies have addressed the response of Amazonian forests to drought by analyzing anomalies in vegetation indices retrieved from satellite sensors. Attention was paid to Amazonia because of two major droughts in 2005 and 2010, which were considered amongst the most severe in a century. These drought events have been associated with increased tree mortality and a temporary shutdown of the Amazon carbon sink. The mortality has been attributed to water stress anomalies, though an additional effect might have resulted from thermal anomalies. Variations in surface temperature are believed to be closely related to drought events, but very few studies have analyzed this variable over the Amazonian region. Here we examine Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) products from the period 2000-2012 in Amazonia. We detected anomalous warming during the dry season (July to September) in the drought years 2005 and 2010, as well as in the years 2009, 2011, and 2012 and to a lesser extent in 2008, which implies anomalous warming in 5 of the last 7years. Recent analysis also shows warming in 2012 from June to August. Land and sea temperature records were also examined using reanalysis data from 1979 to present. Our results show good agreement between MODIS LST and reanalysis data from 2000 to present and a clear link between warming over the Amazonian region and anomalies in sea surface temperature in both the Atlantic and Pacific regions.