Lawrence Berkeley National Laboratory

We investigate spatio-temporal relationships between soil CO2 flux (FCO2), meteorological variables, and topography over a ten-day period (09/12/2006 to 09/21/2006) at the Horseshoe Lake tree kill, Mammoth Mountain, CA. Total CO2 discharge varied from 16 to 52 t d-1, suggesting a decline in CO2 emissions over decadal timescales. We observed systematic changes in FCO2 in space and time in association with a weather front with relatively high wind speeds from the west and low atmospheric pressures. The largest FCO2 changes were observed in relatively high elevation areas. The variations in FCO2 may be due to dynamic coupling of wind-driven airflow through the subsurface and flow of source CO2 at depth. Our results highlight the influence of weather fronts on volcanic gas flow in the near-surface environment and how this influence can vary spatially within a study area.