Coherent structures detected in the unstable atmospheric surface layer above the Amazon forest

Dias-Júnior, Cléo Q.; Sá, Leonardo Deane de Abreu; Pachêco, Vanusa Bezerra; Souza, Cledenilson Mendonça de

doi:10.1016/j.jweia.2012.12.019

Cited by 23 publications

(17 citation statements)

References 37 publications

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“…There is some consensus that CSs are associated with turbulent flows, although there is no full agreement on the percentage of the turbulent fluxes associated with them (Lu and Fitzjarrald, 1994;Thomas and Foken, 2007;Foken et al, 2012). There has been much research on the dominant scale of occurrence of CSs (Collineau and Brunet, 1993;Thomas and Foken, 2005) and the physical mechanisms responsible for their generation (Paw U et al, 1992;Raupach et al, 1996;McNaughton and Brunet, 2002;Campanharo et al, 2008;Dias Júnior et al, 2013). Considerable research has also been devoted to the detection of CSs (Collineau and Brunet, 1993;Krusche and Oliveira, 2004) and the dissimilarity between CSs associated with the transport of momentum and scalars (Li and Bou-Zeid, 2011).…”

Section: Coherent Structure Time Scale Above the Atto Sitementioning

confidence: 99%

“…These variations can be attributed to downward mixing of O 3 , which is "stored" within the canopy (so called storage flux, see Rummel et al, 2007). It is subsequently depleted by chemical reactions, mostly with soil bio- [ppm] Dlugokencky et al, 2014;Cape Verde (green: Carpenter et al, 2010, updated). genic NO, and deposition after the forest canopy becomes decoupled from the atmosphere above at nighttime. During the wet season, the largest decrease in O 3 mixing ratios occurs at the canopy top.…”

Section: Ozone Profilesmentioning

confidence: 99%

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The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

Andreae¹,

Acevedo²,

Araújo³

et al. 2015

Atmos. Chem. Phys.

242

338

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Abstract. The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It has already been changed significantly by human activities, and more pervasive change is expected to occur in the coming decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region, as human perturbations increase in the future.The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at five to eight different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO 2 , and OH reactivity). Aerosol optical, microphysical, and chemical measurements are being made above the canopy as well as in the canopy space. They include aerosol light scattering and absorption, fluorescence, number and volume size distributions, chemical composition, cloud condensation nuclei (CCN) concentrations, and hygroscopicity. In this paper, we discuss the scientific context of the ATTO observatory and present an overview of results from ecological, meteorological, and chemical pilot studies at the ATTO site.

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Section: Coherent Structure Time Scale Above the Atto Sitementioning

confidence: 99%

Section: Ozone Profilesmentioning

confidence: 99%

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

Andreae¹,

Acevedo²,

Araújo³

et al. 2015

Atmos. Chem. Phys.

242

338

View full text Add to dashboard Cite

show abstract

“…Dias‐Júnior et al () recently found that the z i values observed above the Rebio‐Jarú reserve varied over the daytime. They found that z i tends towards a maximum value of 41 m in the early morning and the late afternoon.…”

Section: Resultsmentioning

confidence: 99%

An empirical‐analytical model of the vertical wind speed profile above and within an Amazon forest site

Souza

Dias-Júnior

Tóta

et al. 2015

Meteorological Applications

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ABSTRACT:The present study considers the mean wind velocity profiles measured from a 60 m high tower in the Rebio-Jarú forest (10 ∘ 04.7 ′ S, 61 ∘ 52.0 ′ W), located in the Brazilian northwestern state of Rondônia. The data were collected during the wet season as part of an intensive campaign of the large scale biosphere-atmosphere experiment in Amazonia. Nine cup anemometers were vertically placed to provide a good estimate of the inflection point height of the mean wind velocity profile. The resulting data were used to formulate a mean vertical wind speed profile,ū(z), based on key parameters such as the inflection point height and the leaf area index. The modified hyperbolic tangent function was used to provide a more flexible fit to the experimental data. An exponential term was also added to theū(z) function, so that it can assume the appropriate 's' shape near the ground. Thus, some parameters were incorporated into the analytical profile function to enable more flexibility. The presented results demonstrate that the profile is a good fit to the experimental data measured above and within the Amazon forest canopy.

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“…Coherent structure is well-organized ramp-like motion for scalar time series (Gao and Li, 1993). The typical duration of coherent structure above and within forest canopy is between 14-116 s by the wavelet analysis (Cava et al, 2004;Dias Júnior et al, 2013;Gao and Li, 1993;Lu and Fitzjarrald, 1994;Steiner et al, 2011;Thomas and Foken, 2005). However, some studies detected that the duration of coherent structure increased from unstable to stable conditions (Steiner et al, 2011) or varied within a day (Dias Júnior et al, 2013).…”

Section: Effects Of Time Averaging Of Co 2 Mixing Ratio On Co 2 Storamentioning

confidence: 99%

“…The typical duration of coherent structure above and within forest canopy is between 14-116 s by the wavelet analysis (Cava et al, 2004;Dias Júnior et al, 2013;Gao and Li, 1993;Lu and Fitzjarrald, 1994;Steiner et al, 2011;Thomas and Foken, 2005). However, some studies detected that the duration of coherent structure increased from unstable to stable conditions (Steiner et al, 2011) or varied within a day (Dias Júnior et al, 2013). Other motions such as canopy or gravity waves might significantly contribute to the spectral properties of the scalar time series particularly under stable conditions (Cava et al, 2004;Lee and Barr, 1998;van Gorsel et al, 2011), although they are not as frequent as does the coherent structure.…”

Section: Effects Of Time Averaging Of Co 2 Mixing Ratio On Co 2 Storamentioning

confidence: 99%

Improving the CO2 storage measurements with a single profile system in a tall-dense-canopy temperate forest

Wang

Guo

et al. 2016

Agricultural and Forest Meteorology

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a b s t r a c tThe CO 2 storage (F s ) measurement can contribute significantly to the estimation of the net ecosystem exchange of CO 2 (NEE) especially in tall-canopy forest ecosystems. The F s is often measured with a profile of CO 2 concentration or with an eddy covariance system at the tower top, but few studies investigated potential errors in the F s measurements. We assessed the errors in F s relevant to the vertical distribution of sampling levels and window sizes of averaging time of CO 2 mixing ratio and their effects on NEE in a temperate deciduous forest site in Northeast China using the standardized major axis method. The CO 2 storage per unit height typically decreased with the height increasing, suggesting that the below-canopy layer need a higher spatial resolution. CO 2 storage could be underestimated by up to one third based only on the tower-top measurement. The uncertainty (standard deviation) of the F s decreased with the length of the averaging time window increasing. However, taking time averaging of CO 2 mixing ratio caused significant underestimate of F s , and consequently led to significant underestimates of CO 2 uptake and release at a 30-min time scale. Our results highlight that appropriately combining spatial resolution and temporal resolution (response time for a whole sampling of all levels) is essential to improving the F s estimates with the existing CO 2 profile systems in forest ecosystems. Since the systematic bias and random error in F s estimate with a single profile system are irreconcilable, there is an urgent need to develop a fast response planar-averaging profile or measure the instantaneous vertical-mean concentration to improve the accuracy of F s measurement.

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Coherent structures detected in the unstable atmospheric surface layer above the Amazon forest

Cited by 23 publications

References 37 publications

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

The Amazon Tall Tower Observatory (ATTO): overview of pilot measurements on ecosystem ecology, meteorology, trace gases, and aerosols

An empirical‐analytical model of the vertical wind speed profile above and within an Amazon forest site

Improving the CO2 storage measurements with a single profile system in a tall-dense-canopy temperate forest

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