TRACKING REGIONAL AND GLOBAL TELECONNECTIONS RECORDED BY NORTH AMERICAN SPELEOTHEM RECORDS

Multi-proxy speleothem records from Moaning (MC) and McLean’s Caves (ML) in the western Sierra Nevada foothills document changes in rainfall amount and source that are coeval with stadials and interstadials of the last deglaciation. These and other speleothem oxygen isotope records of deglacial climate in western North America suggest important linkages between precipitation variability in this region and changes in global climate such as Arctic temperature and Asian monsoonal strength. However, these linkages have not yet been systematically investigated. We present a network visualization of 20 high-resolution oxygen isotope records from speleothems covering 10–20 ka, and four other key climate archives from ice cores and marine sediments. Significant positive correlations exist among the majority of North American records, including the Sierra Nevada speleothems, indicating generally coherent patterns of regional climate change at the scale of this analysis. One noteworthy exception to coherence is observed at Cave Without a Name (CWN), located farthest to the southeast in Texas, which shows a strong negative correlation with other regional records.

Important global teleconnections also emerge from our analysis. Strong positive relationships exist between CWN, Hulu (China), Moomi (Yemen), and Chauvet (France) Caves and between these and the Cariaco Basin. Most North American caves display negative correlations with Hulu, Chauvet, and Cariaco. Strong negative relationships emerge between Sanbao (China) and Sofular (Turkey) Caves and between Sofular and the Cariaco Basin. The NGRIP ice core record displays positive correlations with most North American records and negative correlations with Asian and European records, while the EPICA Antarctic ice core record shows positive correlations with some North American records (ML, Fort Stanton, Cave of the Bells). Although some important connections occur between the northern and southern hemispheres, the strongest connections persist across the northern mid-latitudes, highlighting the importance of the Intertropical Convergence Zone and the westerly winds in transmitting information between these regions.