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 United States are correlated with an index of the PNA pattern. The δ18O/PNA relationship varies across the study region and exhibits two prominent modes, with positive correlation in the western USA and negative correlation in the east. This spatial pattern appears not to reflect variation in local climate variables, but rather primarily reflects differences in atmospheric circulation and moisture sources associated with PNA. Our results suggest that strong antiphase variation in paired paleo-water δ18O proxy records from regions characterized by the two modes of δ18O/PNA correlation, especially in the Midwest and southwestern USA, may provide a robust basis for reconstruction of past variation in the PNA pattern.

► Precipitation δ18O values correlate with the PNA pattern across the contiguous USA. ► δ18O/PNA correlation is of opposite sign in the eastern and western USA. ► A δ18O difference index isolates PNA from variation in other climate modes. ► Paleo-isotope data could reveal past changes in atmospheric circulation modes.