North American Hydroclimate Synthesis Graph

Figure 2: Top: the decadal mean extra-tropical Northern Hemisphere temperature anomaly (red line) relative to the 1961–1990 mean and the two standard deviation error bars (light red shading; Ljungqvist, 2010). Bottom: the number of proxy data locations in North America that indicate wet, dry, and neutral century-scale hydroclimate states represented as the difference between the total number of wet and dry sites in the NAHS for 100-year window midpoints from 50 BCE to 1850 CE. Blue shading above “0” on the y-axis highlights the value range where more sites in the NAHS exhibited a wetter climate than the number of sites that exhibited a relatively drier climate, and brown shading below “0” in the y-axis highlights the value range where more sites exhibited a drier climate than a wetter climate. The cross-hatched areas indicate values that exceed one standard deviation from the means of both the thick gray line and the thin black line. The warm Roman Warm Period (RWP) and Medieval Climate Anomaly (MCA) are outlined in solid red lines, and the cool Dark Ages Cold Period (DACP) and Little Ice Age (LIA) are outlined in solid blue lines. (Figure 11 in Rodysill et al., 2018)