Fig. 4.

Comparison of the DLH tree-ring δ¹⁸O precipitation reconstruction with other paleoclimatic records spanning the Holocene. (A) Anomaly percentage of the DLH precipitation reconstruction calculated over the period 4680 BCE to 1950 CE (this study). (B) Pollen-based annual precipitation anomaly percentage in Gonghai Lake calculated over the common period 4680 BCE to 1950 CE (24). (C) Normalized stalagmite composite δ¹⁸O record from eastern China. The y-axis of the composite δ¹⁸O record was reversed for better comparison. Each stalagmite δ¹⁸O record was first normalized over the common period 4700 BCE to 1300 CE using the equation (a − b_m) / b_s, where a is the original value, and b_m and b_s are the mean and SD of the common period, respectively. See SI Appendix, Table S6 (site no.: 1 to 6) for details about each stalagmite record employed in the calculation. (D) Variation in location of the ITCZ reflected by Cariaco Basin Ti concentrations (26). All horizontal lines represent the long-term average calculated over the common period 4680 BCE to 1950 CE. The long-term precipitation average values are 200 and 511 mm, respectively for panels (A and B). For panels (A–D), all series were first interpolated annually by using a piecewise linear interpolation method, and then each series (thin line) was smoothed by a 100-point low-pass filter (heavy line) to highlight the centennial scale variability.