HR: 0800h
AN: B51A-0935    [Abstracts]
TI: The impact of wind on the soil respiration measurement
AU: * Xu, L
EM: lxu@licor.com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AU: Madsen, R
EM: rmadsen@licor.com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AU: Anderson, D
EM: danderson@licor.com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AU: Furtaw, M
EM: mfurtaw@licor,com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AU: Garcia, R
EM: rgarcia@licor,com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AU: McDermitt, D
EM: dmcdermitt@licor.com
AF: Licor Inc, 4421 Superior Street, Lincoln, NE 68504 United States
AB: Soil respiration is a significant component of the carbon balance for an ecosystem, however, how environmental variables regulate the soil respiration remains poorly understood. This limits our ability to understand the carbon budget at the ecosystem level, thus making it uncertain to predict the impact of climate change on soil respiration and its feedback. One major reason for this poor understanding is that we are still lacking continuous long-term soil respiration data at a very high temporal and spatial resolution due to unavailable robust and reliable automated soil respiration instruments. To meet this need, Licor Inc has developed a new automated instrument, the LI-8100, for continuous long-term soil respiration measurements. The instrument also supports a survey chamber for studying the spatial variability of soil respiration. In this paper, we will brief the design, the capability, a new way to compute the respiration rate and other features of the LI-8100. We will then focus on the impact of wind gusts on the soil CO2 efflux. The experiment was carried out in a grassland forest-edge ecosystem near Lincoln, Nebraska in the summer of 2004. Soil respiration rate was measured with our automated soil respiration system (LI-8100). 3D wind speed at 0.5 m was monitored at 1 Hz with a RM Young sonic anemometer. Soil temperature, soil moisture and precipitation were also measured with various instruments and sensors. Results showed that, when there was a sudden change in wind speed, soil respiration rate increased, sometimes by 50% or more. The validity of soil respiration measurements under such windy conditions will be discussed in terms of the pressure difference between the inside and the outside of the respiration chamber.
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting