Influence of advection on measurements of the net ecosystem‐atmosphere exchange of CO2 from a very tall tower

Yi, Chuixiang; Davis, K. J.; Bakwin, Peter S.; Berger, Bernard; Marr, Linsey C.

doi:10.1029/2000jd900080

Cited by 108 publications

(106 citation statements)

References 41 publications

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“…While horizontal and vertical advection make a negligible contribution to daytime NEE determined from eddy covariance (Wang et al, 2005;Yi et al, 2000), our results confirm that horizontal advection does have a large influence on variations in the column even over four hours. We attribute the poor comparison of column drawdown and local NEE on daily timescales to the neglect of advection in Eq.…”

Section: Diurnal Variationssupporting

confidence: 70%

The imprint of surface fluxes and transport on variations in total column carbon dioxide

et al. 2012

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Abstract. New observations of the vertically integrated CO 2 mixing ratio, CO 2 , from ground-based remote sensing show that variations in CO 2 are primarily determined by large-scale flux patterns. They therefore provide fundamentally different information than observations made within the boundary layer, which reflect the combined influence of large-scale and local fluxes. Observations of both CO 2 and CO 2 concentrations in the free troposphere show that large-scale spatial gradients induce synoptic-scale temporal variations in CO 2 in the Northern Hemisphere midlatitudes through horizontal advection. Rather than obscure the signature of surface fluxes on atmospheric CO 2 , these synopticscale variations provide useful information that can be used to reveal the meridional flux distribution. We estimate the meridional gradient in CO 2 from covariations in CO 2 and potential temperature, θ, a dynamical tracer, on synoptic timescales to evaluate surface flux estimates commonly used in carbon cycle models. We find that simulations using Carnegie Ames Stanford Approach (CASA) biospheric fluxes underestimate both the CO 2 seasonal cycle amplitude throughout the Northern Hemisphere midlatitudes and the meridional gradient during the growing season. Simulations using CASA net ecosystem exchange (NEE) with increased and phase-shifted boreal fluxes better fit the observations. Our simulations suggest that climatological mean CASA fluxes underestimate boreal growing season NEE (between 45-65 • N) by ∼40 %. We describe the implications for this large seasonal exchange on inference of the net Northern Hemisphere terrestrial carbon sink.

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Section: Diurnal Variationssupporting

confidence: 70%

The imprint of surface fluxes and transport on variations in total column carbon dioxide

et al. 2012

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“…Yi et al (2000) pointed out that, under convective conditions, the horizontal flux divergence is much smaller than the vertical turbulent flux; this agrees with Wyngaard et al (1971) and Lee (1998). Finnigan (1999) stated that the assumption that the horizontal flux divergence is always much smaller than the vertical turbulent flux cannot be anticipated.…”

Section: Introductionsupporting

confidence: 65%

Estimating the components of the sensible heat budget of a tall forest canopy in complex terrain

Moderow

Feigenwinter

Bernhofer

2006

Boundary-Layer Meteorol

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Ultrasonic wind measurements, sonic temperature and air temperature data at two heights in the advection experiment MORE II were used to establish a complete budget of sensible heat including vertical advection, horizontal advection and horizontal turbulent flux divergence. MORE II took place at the long-term Carbo-Europe IP site in Tharandt, Germany. During the growing period of 2003 three additional towers were established to measure all relevant parameters for an estimation of advective fluxes, primarily of CO 2 . Additionally, in relation to other advection experiments, a calculation of the horizontal turbulent flux divergence is proposed and the relation of this flux to atmospheric stability and friction velocity is discussed. In order to obtain a complete budget, different scaling heights for horizontal advection and horizontal turbulent flux divergence are tested. It is shown that neglecting advective fluxes may lead to incorrect results. If advective fluxes are taken into account, the sensible heat budget based upon vertical turbulent flux and storage change only, is reduced by approximately 30%. Additional consideration of horizontal turbulent flux divergence would in turn add 5-10% to this sum (i.e., the sum of vertical turbulent flux plus storage change plus horizontal and vertical advection). In comparison with available energy horizontal advection is important at night whilst horizontal turbulent flux divergence is rather insignificant. Obviously, advective fluxes typically improve poor nighttime energy budget closure and might change ecosystem respiration fluxes considerably.

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“…The net ecosystem exchange (NEE) is the net flux into or out of the ecosystem, and can be calculated from atmospheric measurements as the sum of the advective flux, the storage flux and the turbulent flux (Lee, 1998;Finnigan, 1999;Yi et al, 2000). Here, the method presented by Winderlich et al (2014) is adopted as it was specifically developed for measurements from multiple levels along a tall tower.…”

Section: Flux Estimationmentioning

confidence: 99%

“…Similar to previous studies (Haszpra et al, 2005;Winderlich et al, 2014) the advective flux component was not included in the calculations as this information was not available. Advective fluxes were shown to depend largely on topography and site characteristics (Aubinet et al, 2005;Feigenwinter et al, 2008) with an estimated contribution of about 10 % of the overall flux for a very tall tower (Yi et al, 2000), but may occasionally be the dominating component. However, these fluxes are difficult to measure and vertical advection is likely to be compensated for by horizontal advection (Feigenwin-ter et al, 2004).…”

Section: Flux Estimationmentioning

confidence: 99%

Continuous CO2/CH4/CO measurements (2012–2014) at Beromünster tall tower station in Switzerland

et al. 2016

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Abstract. The understanding of the continental carbon budget is essential to predict future climate change. In order to quantify CO 2 and CH 4 fluxes at the regional scale, a measurement system was installed at the former radio tower in Beromünster as part of the Swiss greenhouse gas monitoring network (CarboCount CH). We have been measuring the mixing ratios of CO 2 , CH 4 and CO on this tower with sample inlets at 12.5, 44.6, 71.5, 131.6 and 212.5 m above ground level using a cavity ring down spectroscopy (CRDS) analyzer. The first 2-year (December 2012-December 2014) continuous atmospheric record was analyzed for seasonal and diurnal variations and inter-species correlations. In addition, storage fluxes were calculated from the hourly profiles along the tower. The atmospheric growth rates from 2013 to 2014 determined from this 2-year data set were 1.78 ppm yr −1 , 9.66 ppb yr −1 and −1.27 ppb yr −1 for CO 2 , CH 4 and CO, respectively. After detrending, clear seasonal cycles were detected for CO 2 and CO, whereas CH 4 showed a stable baseline suggesting a net balance between sources and sinks over the course of the year. CO and CO 2 were strongly correlated (r 2 > 0.75) in winter (DJF), but almost uncorrelated in summer. In winter, anthropogenic emissions dominate the biospheric CO 2 fluxes and the variations in mixing ratios are large due to reduced vertical mixing. The diurnal variations of all species showed distinct cycles in spring and summer, with the lowest sampling level showing the most pronounced diurnal amplitudes. The storage flux estimates exhibited reasonable diurnal shapes for CO 2 , but underestimated the strength of the surface sinks during daytime. This seems plausible, keeping in mind that we were only able to calculate the storage fluxes along the profile of the tower but not the flux into or out of this profile, since no Eddy covariance flux measurements were taken at the top of the tower.

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Influence of advection on measurements of the net ecosystem‐atmosphere exchange of CO₂ from a very tall tower

Cited by 108 publications

References 41 publications

The imprint of surface fluxes and transport on variations in total column carbon dioxide

The imprint of surface fluxes and transport on variations in total column carbon dioxide

Estimating the components of the sensible heat budget of a tall forest canopy in complex terrain

Continuous CO<sub>2</sub>/CH<sub>4</sub>/CO measurements (2012–2014) at Beromünster tall tower station in Switzerland

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Influence of advection on measurements of the net ecosystem‐atmosphere exchange of CO2 from a very tall tower

Cited by 108 publications

References 41 publications

The imprint of surface fluxes and transport on variations in total column carbon dioxide

The imprint of surface fluxes and transport on variations in total column carbon dioxide

Estimating the components of the sensible heat budget of a tall forest canopy in complex terrain

Continuous CO&lt;sub&gt;2&lt;/sub&gt;/CH&lt;sub&gt;4&lt;/sub&gt;/CO measurements (2012–2014) at Beromünster tall tower station in Switzerland

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Influence of advection on measurements of the net ecosystem‐atmosphere exchange of CO₂ from a very tall tower

Continuous CO<sub>2</sub>/CH<sub>4</sub>/CO measurements (2012–2014) at Beromünster tall tower station in Switzerland