Six-week time series of eddy covariance CO2 flux at Mammoth Mountain, California: Performance evaluation and role of meteorological forcing

Abstract

CO 2 and heat fluxes were measured over a six-week period (09/08/2006 to 10/24/2006) by the eddy covariance (EC) technique at the Horseshoe Lake tree kill (HLTK), Mammoth Mountain, CA, a site with complex terrain and high, spatially heterogeneous CO 2 emission rates. EC CO 2 fluxes ranged from 218 to 3500 g m. Using footprint modeling, EC CO 2 fluxes were compared to CO 2 fluxes measured by the chamber method on a grid repeatedly over a 10-day period. Half-hour EC CO 2 fluxes were moderately correlated (R 2 = 0.42) with chamber fluxes, whereas average daily EC CO 2 fluxes were well correlated (R 2 = 0.70) with chamber measurements. Average daily EC CO 2 fluxes were correlated with both average daily wind speed and atmospheric pressure; relationships were similar to those observed between chamber CO 2 fluxes and the atmospheric parameters over a comparable time period. Energy balance closure was assessed by statistical regression of EC energy fluxes (sensible and latent heat) against available energy (net radiation, less soil heat flux). While incomplete (R 2 = 0.77 for 1:1 line), the degree of energy balance closure fell within the range observed in many investigations conducted in contrasting ecosystems and climates. Results indicate that despite complexities presented by the HLTK, EC can be reliably used to monitor background variations in volcanic CO 2 fluxes associated with meteorological forcing, and presumably changes related to deeply derived processes such as volcanic activity.

Deep CO<sub>2</sub> soil inhalation / exhalation induced by synoptic pressure changes and atmospheric tides in a carbonated semiarid steppe

“…Advection has been detected using isotopic methods (Bowling and Massman, 2011), buried p sensors (Maier et al, 2010;Takle et al, 2004), 222 Rn concentrations (Clemets and Wilkening, 1974;Fujiyoshi et al, 2010), ground-penetrating radar (Comas et al, 2005) or variations in CO 2 and other gases (Seok et al, 2009;Hirsch et al, 2004;Reicosky et al, 2008). Even in volcanoes the atmospheric p has a strong influence on both CO 2 degassing (Rogie et al, 2001) and the CO 2 soil efflux (Granieri et al, 2003), as well as on their combination as measured by eddy covariance (Lewicki et al, 2008;Lewicki et al, 2007).…”

Towards real-time eruption forecasting in the Auckland Volcanic Field: application of BET_EF during the New Zealand National Disaster Exercise ‘Ruaumoko’

“…Future monitoring strategies may include annual surveys of soil gas or other technologies such as eddy covariance to provide background levels of volcanic gases specific to the AVF (e.g. Lewicki et al 2008). …”

A shallow subsurface controlled release facility in Bozeman, Montana, USA, for testing near surface CO2 detection techniques and transport models

“…First, natural analog sites where geologically generated CO 2 rises to the surface such as Mammoth Mountain (Anderson and Farrar 2001;Lewicki et al 2008a) and the Latera caldera in Italy (Annunziatellis et al 2008) have been investigated using a variety of detection technologies which have determined soil gas concentrations and soil gas flux of CO 2 as well as impact on plant life. These sites have a long-established flux and an unknown source term which makes it difficult to establish detection limits for near surface monitoring technologies and hampers transport modeling because flow paths have been long established.…”