A system to measure surface fluxes of momentum, sensible heat, water vapour and carbon dioxide

Moncrieff, John; Massheder, J. M.; Bruin, Henk De; Elbers, J.A.; Friborg, Thomas; Heusinkveld, B.G.; Kabat, P.; Scott, Steve; Soegaard, H.; Verhoef, Anne

doi:10.1016/s0022-1694(96)03194-0

Cited by 956 publications

(613 citation statements)

References 25 publications

Supporting

Mentioning

590

Contrasting

Unclassified

Order By: Relevance

“…Despite an absence of instrumentation, Reynolds (1895) established the fundamental theoretical framework for the eddy covariance approach to flux measurements, and throughout the 20th century, an international group of physical scientists contributed to the theory and instrumentation of flux measurements (Moncrieff et al, 1997;Baldocchi, 2003). In the late 20th century these scientists contributed to a growing understanding of two major environmental problems: the effects of large-scale air pollution that had spread across Europe and North America and the interactions of fossil-fuel-driven increases in atmospheric CO 2 and the ecosystem-atmosphere exchanges of carbon, water, and heat.…”

Section: Fluxnetmentioning

confidence: 99%

Ideas and perspectives: Strengthening the biogeosciences in environmental research networks

et al. 2018

View full text Add to dashboard Cite

Abstract. Long-term environmental research networks are one approach to advancing local, regional, and global environmental science and education. A remarkable number and wide variety of environmental research networks operate around the world today. These are diverse in funding, infrastructure, motivating questions, scientific strengths, and the sciences that birthed and maintain the networks. Some networks have individual sites that were selected because they had produced invaluable long-term data, while other networks have new sites selected to span ecological gradients. However, all long-term environmental networks share two challenges. Networks must keep pace with scientific advances and interact with both the scientific community and society at large. If networks fall short of successfully addressing these challenges, they risk becoming irrelevant. The objective of this paper is to assert that the biogeosciences offer environmental research networks a number of opportunities to expand scientific impact and public engagement. We explore some of these opportunities with four networks: the International Long-Term Ecological Research Network programs (ILTERs), critical zone observatories (CZOs), Earth and ecological observatory networks (EONs), and the FLUXNET program of eddy flux sites. While these networks were founded and expanded by interdisciplinary scientists, the preponderance of expertise and funding has gravitated activities of ILTERs and EONs toward ecology and biology, CZOs toward the Earth sciences and geology, and FLUXNET toward ecophysiology and micrometeorology. Our point is not to homogenize networks, nor to diminish disciplinary science. Rather, we argue that by more fully incorporating the integration of biology and geology in long-term environmental research networks, scientists can better leverage network assets, keep pace with the ever-changing science of the environment, and engage with larger scientific and public audiences.

show abstract

Section: Fluxnetmentioning

confidence: 99%

Ideas and perspectives: Strengthening the biogeosciences in environmental research networks

et al. 2018

View full text Add to dashboard Cite

show abstract

“…This last attenuation is typical of closed-path systems. Specific transfer functions describing the impact of fluctuation attenuation in tubes have been adapted by Leuning and Moncrieff (1990), Lenschow and Raupach (1991), Massman (1991), Leuning and King (1992), Leuning and Judd (1996) and Moncrieff et al (1997). With this formalism, the real (w s ) and measured (w s meas ) covariances of the vertical wind velocity component (w) and the scalar mixing ratio (s) are written, respectively, as:…”

Section: Eddy-covariance Spectral Analysismentioning

confidence: 99%

“…The second hypothesis means explicitly that fluctuation attenuation due to electronic response time or path averaging (at not too high wind speeds) takes place at much higher frequencies than attenuation due to mixing in the tube and from sorption/desorption. Moncrieff et al (1997) have shown that the theoretical transfer functions for the electronic response time and path averaging of the commonly used sonic anemometers show almost no attenuation below 1 Hz and limited attenuation between 1 and 10 Hz. In contrast, attenuation due to mixing in the tube and from sorption/desorption occurs at much lower frequencies, as will be shown later.…”

Section: Eddy-covariance Spectral Analysismentioning

confidence: 99%

“…The major problem derives from the transport of air from the sampling point to the analyser, when air is partially mixed in the filters and in the tube. The high-frequency loss associated with this process has been analysed, notably by Eugster and Senn (1995), Leuning and Judd (1996), Moncrieff et al (1997), Massman (2000) and Aubinet et al (2001), who quantified the high-frequency attenuation with a transfer function.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

New Transfer Functions for Correcting Turbulent Water Vapour Fluxes

Ligne

Heinesch

Aubinet

2010

Boundary-Layer Meteorol

View full text Add to dashboard Cite

We address the problem of the high-frequency correction of water vapour fluxes measured by eddy covariance with a closed-path infrared gas analyser (IRGA). Different transfer functions are compared and evaluated at a forested (Vielsalm, Belgium) and an agricultural (Lonzée, Belgium) site. Classical functions, usually applied to correct CO 2 fluxes (Gaussian, Lorentzian), are found to be unsuited to water vapour cospectral corrections, being characterised by too sharp a decrease at high frequency. Two other functions characterised by a lower decreasing slope are found to better fit experimental transfer functions. They were calibrated and validated on experimental transfer functions and their dependency on air humidity is parameterised. On this basis, new correction coefficients are estimated. The coefficients are found to be larger than those based on the classical functions, even when the dependency of the latter on air humidity is taken into account. The difference amounts to 10% at the forested site and to 5% larger at the crop site. The study highlights the necessity of characterising the water transfer function shape and taking it into account in the correction factor at each site equipped with a closed path IRGA.

show abstract

“…For H 2 O and CO 2 measurements, a closed-path differential infrared absorption analyzer (LI-COR LI-6262, USA) with a nominal response time of 0.1 s was used (see e.g. Ammann, 1999;Aubinet et al, 2000;Moncrieff et al, 1997). The fast O 3 analyzer (GFAS, Germany) is based on the surface chemiluminescence reaction of O 3 with a coumarin dye layer on an aluminum plate placed in the sample air stream (Ammann, 1999;Güsten et al, 1992;Güsten and Heinrich, 1996).…”

Section: Eddy Covariance Flux Systemmentioning

confidence: 99%

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

et al. 2007

View full text Add to dashboard Cite

Abstract. Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution toLarge-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH), we performed tower-based eddy covariance measurements of O 3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O 3 sink with a mean daytime (midday) maximum deposition velocity of 2.3 cm s −1 , and a corresponding O 3 flux of −11 nmol m −2 s −1 . At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb) than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O 3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s −1 . The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO) was found to contribute substantially to the O 3 sink in the rain forest canopy. Further contributions Correspondence to: U. Rummel (udo.rummel@dwd.de) were from non-stomatal plant uptake and other processes that could not be clearly identified.Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O 3 dry deposition values from this site with typical vegetation cover of deforested land in southwest Amazonia to the results from the primary rain forest. The mean ozone deposition to the pasture was found to be systematically lower than that to the forest by 30% in the wet and 18% in the dry season.

show abstract

A system to measure surface fluxes of momentum, sensible heat, water vapour and carbon dioxide

Cited by 956 publications

References 25 publications

Ideas and perspectives: Strengthening the biogeosciences in environmental research networks

Ideas and perspectives: Strengthening the biogeosciences in environmental research networks

New Transfer Functions for Correcting Turbulent Water Vapour Fluxes

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

Contact Info

Product

Resources

About