Statistics of Surface-Layer Turbulence Over Terrain with Metre-Scale Heterogeneity

Andreas, Edgar L.; Hill, R. J.; Gosz, James R.; Moore, Douglas I.; Otto, William D.; Sarma, A. D.

doi:10.1023/a:1000609131683

Cited by 108 publications

(69 citation statements)

References 36 publications

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“…These surfaces may be homogeneous for the sinks and sources of heat while heterogeneous for water vapor. Similar phenomena were reported in earlier studies Andreas et al 1998). Therefore, the horizontal advection of sensible heat may be neglected, while that of latent heat might be important.…”

Section: Discussion On Energy Closure Problemsupporting

confidence: 84%

Analysis of the Surface Energy Budget at a Site of GAME/Tibet using a Single-Source Model

Yang

Koike

Ishikawa

et al. 2004

Journal of the Meteorological Society of Japan

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In the GAME/Tibet project, the Anduo site is a typical plateau prairie area that is covered by short and sparse vegetation. From May to September 1998, we measured all the surface energy fluxes at this site to quantitatively describe the surface energy budget, but it was still questionable because of low energy closure ratios in most days of the rainy season.To clarify the surface energy budget at this site, this study proposes a single-source energy partition model, to simplify the processes of heat and water vapor transfer from the surface. The model does not distinguish the contribution of turbulent fluxes from the vegetation, and the one from the ground, and thus has fewer parameters to be calibrated comparing to a dual-source model. The main model parameters are: the soil surface evaporation resistance, the parameter kB À1 (the logarithm of the ratio of the aerodynamic roughness length to the thermal roughness length), and the surface emissivity. Their values are calibrated by minimizing the discrepancy between measured and model-predicted values of soil temperatures.This tuned single-source model is then validated by the agreement between the measured and simulated net radiation flux, surface soil heat flux, sensible heat flux, and latent heat flux on the days with high energy closure ratios. This model also reproduces these measured fluxes, except latent heat flux on the days with low closure ratios. The simulated latent heat flux is much higher than the measured one. We further show that the measured latent heat flux is untrustable due to an instrumental limitation, while the model provides a reasonable surrogate. Therefore, the single-source concept is applicable to the heat and water vapor transfer on the Tibetan plateau sparse-vegetation surface, and would contribute to a further research on the land-atmosphere interactions over the plateau.

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Section: Discussion On Energy Closure Problemsupporting

confidence: 84%

Analysis of the Surface Energy Budget at a Site of GAME/Tibet using a Single-Source Model

Yang

Koike

Ishikawa

et al. 2004

Journal of the Meteorological Society of Japan

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“…Grachev et al [2005] explained that, in the SHEBA data set, this moisture correction was negligible because of the very small latent heat fluxes. Andreas et al [1998] likewise showed that this moisture correction is negligible when the Bowen ratio is large, which translates to jBoj greater than roughly 0.5 for the sea ice sets. Hence, there is no humidity correction in the Ice Station Weddell sensible heat fluxes , but the SHEBA sensible heat fluxes do include this Andreas [2005].…”

Section: Appendix B: Measurement Detailsmentioning

confidence: 91%

“…[6] Besides its relevance to the energy budget, other uses of the Bowen ratio are in interpreting sonic anemometer data [Schotanus et al, 1983;Andreas et al, 1998] and in specifying the Obukhov length, the stratification parameter in the atmospheric surface layer, when the latent heat flux is unknown [e.g., Busch, 1973;Andreas, 1992]. Wesley [1976], Kunkel and Walters [1983], Andreas [1988], and Green et al [2001] showed how electromagnetic propagation in the surface layer is sensitive to the Bowen ratio.…”

Section: Introductionmentioning

confidence: 99%

Estimating the Bowen ratio over the open and ice‐covered ocean

Andreas

Jordan²,

Mahrt

et al. 2013

JGR Oceans

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[1] The Bowen ratio, the ratio of the turbulent surface fluxes of sensible (H s ) and latent (H L ) heat, Bo H s /H L , occurs throughout micrometeorology. It finds application in the Bowen ratio and energy budget method, where it provides both turbulent heat fluxes when only the available energy at the surface is known. It can yield an estimate of a missing H s or H L if the other flux is known. We also suggest that the Bowen ratio may provide the missing piece needed to infer the surface sensible heat flux from satellite data. For this study, we analyze almost 9000 eddy-covariance measurements of H s and H L . About half were made over sea ice; the other half, over the open ocean. These are saturated surfaces where the surface specific humidity is the saturation value at the surface temperature. Surface temperatures ranged from À44 C to 32 C and predict the Bowen ratio through the Bowen ratio indicator,Here c p is the specific heat of air at constant pressure, L v is the latent heat of sublimation or vaporization, and @Q sat =@Â is the derivative of the saturation specific humidity (Q sat ) with temperature (Â). All quantities are evaluated at the surface temperature, Â s . Although H s and H L can occur in nine possible combinations, in our data set, three combinations represent over 90% of the cases: H s > 0 and H L > 0, H s < 0 and H L < 0, and H s < 0 and H L > 0. In each of these three cases, the data suggest Bo ¼ aBo Ã , where a is 0.40, 3.27, and À0.65, respectively.

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“…In both cases scalar similarity increased with ecosystem recovery up to pre-cutting values. The lack of scalar similarity after the management confirms dependence on plant physiology and source/sink influences (Andreas et al, 1998a;Ruppert et al, 2006b;Held et al, 2008;Ruppert, 2008). In general, it is suggested that REA not be applied shortly after management events due to the fact that b can only be properly determined before management events and after an adequate period of ecosystem recovery.…”

Section: Simulation Of Rea On Managed Grasslandmentioning

confidence: 92%

“…This means that scalar quantities are transported with similar efficiency by turbulence elements of diverse characteristics (Ruppert et al, 2006b). Differences in distribution (Andreas et al, 1998a;Ruppert et al, 2006b;Held et al, 2008), amount and strength of scalar sources and sinks are reasons for differences in turbulent exchange of the scalars and for lacking scalar similarity. Furthermore, scalar similarity is influenced by the seasonal variation in canopy physiology .…”

Section: Rea Theory and Frameworkmentioning

confidence: 99%

Prerequisites for application of hyperbolic relaxed eddy accumulation on managed grasslands and alternative net ecosystem exchange flux partitioning

et al. 2014

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Abstract.Relaxed eddy accumulation is still applied in ecosystem sciences for measuring trace gas fluxes. On managed grasslands, the length of time between management events and the application of relaxed eddy accumulation has an essential influence on the determination of the proportionality factor b and thus on the resulting flux. In this study this effect is discussed for the first time. Also, scalar similarity between proxy scalars and scalars of interest is affected until the ecosystem has completely recovered. Against this background, CO 2 fluxes were continuously measured and 13 CO 2 isofluxes were determined with a high measurement precision on two representative days in summer 2010.Moreover, a common method for the partitioning of the net ecosystem exchange into assimilation and respiration based on temperature and light response was compared with an isotopic approach directly based on the isotope discrimination of the biosphere. This approach worked well on the grassland site and could enhance flux partitioning results by better reproducing the environmental conditions.

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Statistics of Surface-Layer Turbulence Over Terrain with Metre-Scale Heterogeneity

Cited by 108 publications

References 36 publications

Analysis of the Surface Energy Budget at a Site of GAME/Tibet using a Single-Source Model

Analysis of the Surface Energy Budget at a Site of GAME/Tibet using a Single-Source Model

Estimating the Bowen ratio over the open and ice‐covered ocean

Prerequisites for application of hyperbolic relaxed eddy accumulation on managed grasslands and alternative net ecosystem exchange flux partitioning

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