The Contribution of Advective Fluxes to Net Ecosystem Exchange in a High‐elevation, Subalpine Forest

Yi, Chuixiang; Anderson, Dean E.; Turnipseed, Andrew A.; Burns, Sean P.; Sparks, Jed P.; Stannard, David I.; Monson, Russell K.

doi:10.1890/06-0908.1

Cited by 87 publications

(81 citation statements)

References 28 publications

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“…Half hourly means of the measured variables were used further for the calculations, following both Feigenwinter et al (2008), where the same data were analysed, and other studies for FLUXNET sites (e.g., Feigenwinter et al, 2004;Aubinet et al, 2005;Heinesch et al, 2007;Turnipseed et al, 2004, Staebler andFitzjarrald, 2004;Yi et al, 2008).…”

Section: Procedures To Calculate the 3-d Fields Of The Physical Quantmentioning

confidence: 99%

“…Goulden et al, 1996;Suyker et al, 2005;Moureaux et al, 2006;Zhao et al, 2006); and (ii) the "correction approach", based on a direct estimation of all the CO 2 balance terms, including the advection terms (e.g. Aubinet et al, 2003Aubinet et al, , 2005Feigenwinter et al, 2004;Staebler and Fitzjarrald, 2004;Marcolla et al, 2005;Sun et al, 2007;Yi et al, 2008;Montagnani et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

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Application of a mass consistent flow model to study the CO2 mass balance of forests

Canepa

Georgieva

Manca

et al. 2010

Agricultural and Forest Meteorology

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The reconstruction of the wind field is one of the main issues in the mass conservation approach for calculation of CO 2 advection in forest ecosystems and still remains a challenging problem. In the current study, we present an advancement of this approach: the use of a mass consistent flow model (WINDS) which takes into account measured wind data and simulates the 3-D flow field, while imposing air mass conservation in the control volume. We apply the WINDS model to calculate half hourly mean total advective flux terms at the arboEurope-IP site of Renon (Bozen/Bolzano Autonomous Province), in Northern Italy. The data used refer to six time periods of one day representing three different meteorological conditions observed during the ADVEX campaign from April to September 2005. Current results are compared with results obtained in two other studies for the same time periods. One of these studies is based on the mass conservation approach as well, but applies only interpolations to reconstruct the wind field; the other study makes use of tilt correction (sectorwise planar fit method) for the vertical wind component. In the present study, the effect of the wind field reconstruction method on the estimation of the advective fluxes is discussed. The possibility of using reduced input wind data (i.e. number of towers) for WINDS is also investigated. The results suggest that the representativeness of wind tower measurements is of primary importance for estimating CO 2 advection terms and their uncertainty in complex terrain.

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Section: Procedures To Calculate the 3-d Fields Of The Physical Quantmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of a mass consistent flow model to study the CO2 mass balance of forests

Canepa

Georgieva

Manca

et al. 2010

Agricultural and Forest Meteorology

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“…Sampling intervals interact systematically with the autocorrelation of the time series arising from the eddy structures (Woodruff, 1986). Integrating volumes (known also as buffer volumes) have been used in previous studies to dampen temporal fluctuations in trace gas mole fractions for flux-gradient measurements (Griffith et al, 2002), for contributions of advection (Yi et al, 2008), and for flask sampling (Bowling et al, 2003). A block-averaging effect is accomplished in flux-gradient measurements that trap the compound of interest over periods of minutes or hours (Müller et al, 1993;Goldstein et al, 1995Goldstein et al, , 1996Goldstein et al, , 1998Meyers et al, 1996) and eddy accumulation methods that use high-precision differential collection apparatus to trap and then sample air from upand down-drafts to determine the flux (Businger and Onlcey, 1990;Guenther et al, 1996;Bowling et al, 1998).…”

Section: Sampling Errormentioning

confidence: 99%

“…Periods with u * < 0.07 m s −1 and u * < 0.17 m s −1 were excluded for below-and above-canopy data, respectively, because of poorly developed turbulent conditions Liu and Foken, 2001;Bocquet et al, 2011) and potential for advective fluxes driven by drainage flows on sloping terrain (Yi et al, 2008). We excluded unrealistic values of the implied turbulent transfer coefficients, K, such that 0 ≤ K ≤ 0.5 m 2 s −1 and 0 ≤ K ≤ 5 m 2 s −1 for the belowcanopy and the whole/above-canopy fluxes, respectively.…”

Section: Data Filteringmentioning

confidence: 99%

Ecosystem fluxes of hydrogen: a comparison of flux-gradient methods

et al. 2014

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Abstract. Our understanding of biosphere-atmosphere exchange has been considerably enhanced by eddy covariance measurements. However, there remain many trace gases, such as molecular hydrogen (H 2 ), that lack suitable analytical methods to measure their fluxes by eddy covariance. In such cases, flux-gradient methods can be used to calculate ecosystem-scale fluxes from vertical concentration gradients. The budget of atmospheric H 2 is poorly constrained by the limited available observations, and thus the ability to quantify and characterize the sources and sinks of H 2 by fluxgradient methods in various ecosystems is important. We developed an approach to make nonintrusive, automated measurements of ecosystem-scale H 2 fluxes both above and below the forest canopy at the Harvard Forest in Petersham, Massachusetts, for over a year. We used three flux-gradient methods to calculate the fluxes: two similarity methods that do not rely on a micrometeorological determination of the eddy diffusivity, K, based on (1) trace gases or (2) sensible heat, and one flux-gradient method that (3) parameterizes K. We quantitatively assessed the flux-gradient methods using CO 2 and H 2 O by comparison to their simultaneous independent flux measurements via eddy covariance and soil chambers. All three flux-gradient methods performed well in certain locations, seasons, and times of day, and the best methods were trace gas similarity for above the canopy and K parameterization below it. Sensible heat similarity required several independent measurements, and the results were more variable, in part because those data were only available in the winter, when heat fluxes and temperature gradients were small and difficult to measure. Biases were often observed between flux-gradient methods and the independent flux measurements, and there was at least a 26 % difference in nocturnal eddy-derived net ecosystem exchange (NEE) and chamber measurements. H 2 fluxes calculated in a summer period agreed within their uncertainty and pointed to soil uptake as the main driver of H 2 exchange at Harvard Forest, with H 2 deposition velocities ranging from 0.04 to 0.10 cm s −1 .

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“…Several campaigns aiming at directly measuring advection have been designed recently (Aubinet et al, 2003;Feigenwinter et al, 2004;Fitzjarrald, 2004, 2005;Marcolla et al, 2005;Heinesch et al, 2007Heinesch et al, , 2008Tóta et al, 2008;Sun et al, 2007;Leuning et al, 2008;Yi et al, 2008). However, these different experiments are difficult to compare as the results are sensible to the design of the experimental setup and the applied methodology to derive the fluxes from measurements.…”

Section: Introductionmentioning

confidence: 99%