HR: 1330h
AN: A52C-0814    [PDF]
TI: Robust$CO{2}$ Flux and $CO{2}$ Concentration Measurements in a Mid-Latitude Wetlands Environment
AU: * Choi, Y
EM: y.choi@larc.nasa.gov
AF: NRC, NASA LaRC, NASA Langley Research Center Chemistry and Dynamics Branch MS483, Hampton, VA 23681 United States
AU: Vay, S
EM: Stephanie.A.Vay@nasa.gov
AF: NASA LaRC, NASA Langley Research Center Chemistry and Dynamics Branch MS483, Hampton, VA 23681 United States
AU: Anderson, B
EM: b.e.anderson@larc.nasa.gov
AF: NASA LaRC, NASA Langley Research Center Chemistry and Dynamics Branch MS483, Hampton, VA 23681 United States
AU: Thornhill, L
EM: k.l.thornhill@larc.nasa.gov
AF: SAIC, NASA LaRC, NASA Langley Research Center Chemistry and Dynamics Branch MS483, Hampton, VA 23681 United States
AB: Wetlands (both coastal and inland) have been identified as significant sinks of carbon and are estimated to store as much as 40 % of the global terrestrial carbon, although they cover only about 3-4 % of the world's land area. Thus they play an important role in the global carbon cycle and are sensitive indicators of climate change. While the sequestration and release of carbon from wetland areas to the atmosphere are controlled by complicated biogeochemical processes, the measurement of CO${2}$ fluxes in wetland environments can provide valuable information on global carbon dynamics. The development of instrument systems capable of accurately measuring the biosphere/atmosphere exchange of CO${2}$ is very important to achieving an understanding of this process. Laboratory experiments have been conducted to evaluate the overall performance of the LICOR- 7000 IRGA for flux measurements and to improve the resulting flux system signal-to-noise ratio. Since perturbations in relative humidity can affect the infrared absorption of CO${2}$, the effect of water vapor mixing ratios ranging from 100 to 30,000 ppmv on predetermined CO${2}$ concentrations were tested. The differences of measured CO${2}$ concentration with a predetermined CO${2}$ concentration between lowest and highest water vapor mixing ratios in the sample flow after it passed the dryer were less than 0.1 ppmv. The CO${2}$ instrumentation and supporting meteorological equipment was subsequently mounted on a tower situated in a local marsh to initiate flux measurements and the results of these observations will be presented. The resulting simultaneous, high precision, fast-response CO${2}$ flux and concentration measurement capability will contribute to elucidating the effects of recent global environmental change on wetland ecosystems and to reducing the uncertainty in our understanding of global carbon cycle.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting