Precipitation Isotope Ratios and Tree-ring based Snowpack Relationships to inform Paleoclimate Reconstructions
PI: Dr. Spruce Schoenemann, University of Montana Western Environmental Sciences
Rocky Mountain snowpack over the recent 30-40 years has shown an unprecedented decline, yet extended observations of snowpack are few. Modern era satellite-derived estimates of snowcover provide valuable snowpack information for water resource managers, yet our understanding of how Rocky Mountain snowpack has responded during previous warm periods is incomplete. Quantitative isotope-based paleoclimate reconstructions, in conjunction with treering climate histories can provide critical information on the impact of past climate variability on mountain water storage. Tree-ring based 1 April Snow Water Equivalent (SWE) reconstructions in the Northern Rocky Mountains have extended the temporal history of snowpack changes to ~1200 A.D. In combination with carbonate isotope lake sediments, there is potential for extending winter season hydroclimate relationships through the Holocene epoch, providing a long-term record of snowpack and climate variability that integrates internal dynamics to orbitalscale forcings. Records will provide a unique insight on the mid-Holocene (~8−5 ka) climatic optimum when temperatures were analogous to the present-day, and will help anticipate snow derived water availability in a warmer future. Thus, the primary goals of this research are to:
- Produce a multi-millennial, winter-spring season paleoclimate reconstruction from tree ring and lake sediment isotope data for the Upper Missouri headwaters region in southwest Montana
- Use NASA MERRA reanalysis products to calibrate historical records with modern conditions
- Integrate historical records with instrumental data to anticipate future climate-snowpack isotope relationships.