Authors: Erika Wise*, University of North Carolina at Chapel Hill, Stephanie McAfee, University of Nevada, Reno, Adam Csank, University of Nevada, Reno
Topics: Climatology and Meteorology, Paleoenvironmental Change, Water Resources and Hydrology
Keywords: dendrochronology, dendroclimatology, biogeography, precipitation, climate, tree rings, snow, precipitation, isotopes, paleoclimate
Session Type: Paper
Start / End Time: 1:10 PM / 2:50 PM
Room: Marshall East, Marriott, Mezzanine Level
Presentation File: No File Uploaded
The tree-ring record is one of the most importance sources of information for understanding pre-instrumental hydroclimate, including drought, precipitation, and streamflow. In western North America, reconstructions typically produce information on a single season or are used to summarize yearly conditions. From a water resources perspective, though, the timing and form of precipitation can be as important as the total amount received over a given time period. This is particularly true on the North American West Coast, where snow is vital for water supply and atmospheric river events can provide 30-50% of annual precipitation in just a few storm events. For this study, we collected tree-ring cores from six sites in the U.S. Pacific Northwest. We measured 10 different metrics in these samples from 1950-2016: widths, d18O, and d13C from total ring, earlywood, and latewood, as well as blue intensity. We used these metrics to investigate the potential for distinguishing multiple seasons of precipitation, rain from snow, and atmospheric river events. We found that while all metrics provide precipitation information, particularly in the cool season, the individual measures can be used to distinguish the form and season of precipitation. The d18O isotopes, in particular, provided more consistent information across seasons, and earlywood d18O contained a clear snow signal. These results indicate that the incorporation of multiple tree-ring metrics will allow for a more comprehensive view of past precipitation patterns.