Pacific/North American teleconnection controls on precipitation isotope ratios across the contiguous United States

Large-scale climate teleconnections such as the Pacific/North American (PNA) pattern strongly influence atmospheric processes and continental climate. Here we show that precipitation δ18O values in the contiguous U.S.A are correlated with an index of the PNA pattern. The δ18O/PNA relationship varies across the study region and exhibits two prominent poles, with positive correlation west of the Rocky Mountain front and negative correlation to the east. This spatial pattern can be attributed primarily to differences in zonal and meridional circulation associated with negative and positive PNA phase. We also show that the δ18O/temperature relationship varies with PNA phase, with higher slope and lower intercept in the western United States, but lower slope and higher intercept in the eastern United States during the negative PNA phase compared to the positive PNA phase. Our results suggest that anti-phase variation in paired paleo-water δ18O from the pole regions, especially in the Upper Midwest and the Colorado Plateau, may provide a robust basis for reconstruction of past variation in the PNA pattern.