Given an isotopically homogeneous or heterogeneous snowpack of known composition, can we predict the isotopic composition of the meltwater as a function of time? By studying this problem we hope to improve the isotopic value used for snow melt in hydrographic separation studies, and to better understand: how the snow pack melts, rain on snow events, the ‘acid flush’ seen during the first phases of snow melt, and the amount and isotopic composition of water that moves into the soil. To address this question we sampled meltwater from lysimeters at two sites with very different winter regimes, Sleeper River watershed in Vermont and Central Sierra Snow Laboratory in California. Snow and other precipitation was collected at each site for large events (> 10 cm of snow, >2 cm rain) and the snow pack near the lysimeter was also sampled throughout the season to determine changes in its’ isotopic composition. Also, after each large snow fall we misted the snow surface over each lysimeter with a 2 ppm solution of a rare earth element. Different rare earth elements were used for sucessive snow layers. By combining chemical markers with data on the isotopic composition of the snow layers we hope to obtain information on how the snow pack melts and determine if, for isotopically heterogeneous snow packs, isotopes alone yield this information. Our first year’s data will be presented.

#Assistant Professor
Dept. Earth Sciences
Dartmouth College
Hanover, N.H. 03755
U.S.A.
Tel: (603) 646-1712
E-mail: Xiahong.Feng@Dartmouth.edu

@Central Sierra Snow Lab.
California
Tel: (530) 426-0318
E-mail: randall@sierra.net