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C <br />cD <br />0 <br />Q <br />D <br />m <br />0 <br />m <br />m <br />0 <br />0 <br />0 <br />ca <br />n' <br />Q <br />0 <br />A <br />N' <br />r4 <br />N <br />O� <br />NO <br />N <br />TABLE 1. Paleodrought data sources and characteristics. <br />Proxy data <br />Continuous <br />Length of <br />Dating Spatial <br />coverage* Limitations and potential biases <br />source <br />record? <br />records <br />Resolution accuracy <br />Early <br />Not always <br />Years— <br />Daily— Day —month Local Quality of instruments and collection of data <br />;nstnlmental <br />decades <br />monthly inconsistent <br />;Tree rings Yes Centuries— Seasonal— Year Local to (a) Dry extremes more reliably represemeo <br />millennia annual —300 km than wet, <br />(b) quantitative reconstructions limited to <br />"analog" conditions within range of ' <br />instrumental variations <br />Alluvial sediments No Millennia Century ±2 % —S% (1dC) Local Fluvial response to climate change not <br />well constrained <br />Flooded trees No Millennia Annual— century 2 0/&-10% (14C) Local (a) Little of this type of data available, <br />year (dendrochrono- (b) rising lake levels inferred from tree deaths, <br />logically dated) (c) timing of lake level drop difficult to <br />estimate <br />*Spatial coverages listed refer to general spatial representativeness of a single site. Some proxy sources (e.g., tree rings) have been used to reconstruct much broader -scale climatic <br />variability when sufficient networks of sites are available. <br />* *The age models of the original peer- reviewed papers were used, after checking to make sure they were internally and regionally consistent, based on common 1T half -life and <br />converted to calendar years (i.e., Stuiver and Polach 1977; Stuiver and Becker 1986) <br />