Year Established: 2016 Start Date: 2016-03-01 End Date: 2018-02-28
Total Federal Funds: $39,012 Total Non-Federal Funds: $79,355
Principal Investigators: Steven Bacon, Rina Schumer
Abstract: Proxy-based hydroclimate records are used to validate regional- to global-scale paleoclimate models and anticipate environmental effects of climate change. The purpose of the proposed study is to develop an annually resolved, 8000-year record of hydroclimate (precipitation and temperature) in the southern Sierra Nevada region. Historical Owens Lake water levels will be reconstructed through correlation of output from a coupled water balance and lake evaporation model with North Americas longest tree-ring record, the Methuselah Walk chronology from the White Mountains. The hydrologic budget will be estimated using a modified version of the Thornthwaite model for runoff and the Hargreaves and Samani empirical equation for lake evaporation, and estimates of precipitation on the lake. These model components require historical monthly temperature and/or precipitation interpolated data from the Parameter-elevation Relationships on Independent Slopes Model (PRISM). The water balance model will be calibrated with the historical Owens Lake water level estimates based on the City of Los Angeles gauged discharge records for the 75-year period between 1915 and 1988, and also the 8000-year shoreline and sediment core chronologies of Owens Lake previously developed by the PI. Proposed work will be unique because it: 1) will produce a chronology that is ~6000 years longer than similar records in the western United States and will represent the longest tree ring based reconstruction of streamflow and associated lake-level fluctuations in North America, 2) will be the first to combine both precipitation-sensitive and temperature-sensitive tree-ring chronologies to reconstruct a hydrologic system, 3) will be performed on a watershed that, due to its shallow basin configuration, is more sensitive to hydroclimatic variability than any other major basin on the east side of the Sierra Nevada, and 4) will be the first to apply variable estimates of solar insolation values through time to the evaporation component of the water balance. This modeling approach developed here will be applicable to the numerous snowmelt-dominated terminal lake basins in Nevada where no gaged streamflow records exist.