Figure 1
From: Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
Precipitation and low level atmospheric circulation (a) and paleorecords compilation for tropical South America (b). (a) Long-term (1981–2010) averaged terrestrial precipitation (color scale) from the University of Delaware (http://climate.geog.udel.edu/~climate/) and 850 hPa wind field (vectors) from the NOAA/OAR/ESRL PSD (http://www.esrl.noaa.gov/psd/) during austral summer (December-January-February, DJF). Thick green arrow marks the South American low level jet (SALLJ). (b) Compilation of hydroclimate records, expressed as the difference between Heinrich Stadial 1 (HS1, 18-15 ka) and the Last Glacial Maximum (LGM, 23-19 ka). Symbol color indicates drier (red), wetter (blue), similar (grey) and unclear (white) conditions during HS1 in comparison to the LGM. Symbol size denotes the quality of the age model based on the chronological reliability index (CRI) (see Supplementary Information). Paleoclimate records with CRI values > 1 are numbered (Supplementary Table S1). Black dashed lines mark the schematic location of the Intertropical Convergence Zone (ITCZ) during austral summer (DJF) and austral winter (June-July-August, JJA). The Amazon River drainage basin is outlined by the black solid line in both panels (a,b). The map was plotted by using the ArcGIS software (version 10, https://software.zfn.uni-bremen.de/software/arcgis/).
