The robustness of eddy correlation fluxes for Amazon rain forest conditions
We analyzed errors and uncertainties in time-integrated eddy correlation data for sites in the Amazon. A well-known source of potential error in eddy correlation is through possible advective losses of CO2 emissions during calm nights. There are also questions related to the treatment of low frequen...
| Autor principal: | Kruijt, Bart J. |
|---|---|
| Outros Autores: | Elbers, Jan A., Von Randow, Celso, Araüjo, Alessandro Carioca de, Oliveira, Paulo J.C., Culf, Alistair D., Manzi, Antônio Ocimar, Nobre, Antônio Donato, Kabat, Pavel, Moors, Eddy J. |
| Grau: | Artigo |
| Idioma: | English |
| Publicado em: |
Ecological Applications
2020
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| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/18904 |
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oai:repositorio:1-18904 |
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oai:repositorio:1-18904 The robustness of eddy correlation fluxes for Amazon rain forest conditions Kruijt, Bart J. Elbers, Jan A. Von Randow, Celso Araüjo, Alessandro Carioca de Oliveira, Paulo J.C. Culf, Alistair D. Manzi, Antônio Ocimar Nobre, Antônio Donato Kabat, Pavel Moors, Eddy J. Carbon Dioxide Carbon Flux Eddy Covariance Error Analysis Rainforest Uncertainty Analysis Amazonia South America We analyzed errors and uncertainties in time-integrated eddy correlation data for sites in the Amazon. A well-known source of potential error in eddy correlation is through possible advective losses of CO2 emissions during calm nights. There are also questions related to the treatment of low frequencies, non-horizontal flow, and uncertainties in, e.g., corrections for tube delay and frequency loss, as well as the effect of missing data. In this study, we systematically explore these issues for the specific situation of flux measurements at two Amazon forest sites. Results indicate that, for this specific environment with tall forest and tall towers, errors and uncertainties caused by data spikes, delay corrections, and high-frequency loss are small (<3% on an annual basis). However, sensitivities to the treatment of low frequencies and non-horizontal flow can be large, especially if the landscape is not homogeneous. Given that there is no consensus on methodology here, this represents an uncertainty of 10-25% on annual total carbon uptake. The other large uncertainty is clearly in the nighttime fluxes. Two different ways to evaluate the validity of these fluxes resulted in at least a 100% difference of annual totals. Finally, we show that uncertainty (standard errors) associated with data gaps can be reduced to <0.5 Mg·ha -1·yr-1 if data are covering at least half of the time, with random spread. Overall uncertainty, on annual CO2 fluxes, excluding the nighttime dilemma, is estimated at ±12% (central Amazon site) to ±32% (southwest Amazon site). Additionally, the nighttime uncertainty is of similar magnitude as the time-integrated fluxes themselves. 2020-06-15T22:03:49Z 2020-06-15T22:03:49Z 2004 Artigo https://repositorio.inpa.gov.br/handle/1/18904 en Volume 14, Número 4 SUPPL., Pags. S101-S113 Restrito Ecological Applications |
| institution |
Instituto Nacional de Pesquisas da Amazônia - Repositório Institucional |
| collection |
INPA-RI |
| language |
English |
| topic |
Carbon Dioxide Carbon Flux Eddy Covariance Error Analysis Rainforest Uncertainty Analysis Amazonia South America |
| spellingShingle |
Carbon Dioxide Carbon Flux Eddy Covariance Error Analysis Rainforest Uncertainty Analysis Amazonia South America Kruijt, Bart J. The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| topic_facet |
Carbon Dioxide Carbon Flux Eddy Covariance Error Analysis Rainforest Uncertainty Analysis Amazonia South America |
| description |
We analyzed errors and uncertainties in time-integrated eddy correlation data for sites in the Amazon. A well-known source of potential error in eddy correlation is through possible advective losses of CO2 emissions during calm nights. There are also questions related to the treatment of low frequencies, non-horizontal flow, and uncertainties in, e.g., corrections for tube delay and frequency loss, as well as the effect of missing data. In this study, we systematically explore these issues for the specific situation of flux measurements at two Amazon forest sites. Results indicate that, for this specific environment with tall forest and tall towers, errors and uncertainties caused by data spikes, delay corrections, and high-frequency loss are small (<3% on an annual basis). However, sensitivities to the treatment of low frequencies and non-horizontal flow can be large, especially if the landscape is not homogeneous. Given that there is no consensus on methodology here, this represents an uncertainty of 10-25% on annual total carbon uptake. The other large uncertainty is clearly in the nighttime fluxes. Two different ways to evaluate the validity of these fluxes resulted in at least a 100% difference of annual totals. Finally, we show that uncertainty (standard errors) associated with data gaps can be reduced to <0.5 Mg·ha -1·yr-1 if data are covering at least half of the time, with random spread. Overall uncertainty, on annual CO2 fluxes, excluding the nighttime dilemma, is estimated at ±12% (central Amazon site) to ±32% (southwest Amazon site). Additionally, the nighttime uncertainty is of similar magnitude as the time-integrated fluxes themselves. |
| format |
Artigo |
| author |
Kruijt, Bart J. |
| author2 |
Elbers, Jan A. Von Randow, Celso Araüjo, Alessandro Carioca de Oliveira, Paulo J.C. Culf, Alistair D. Manzi, Antônio Ocimar Nobre, Antônio Donato Kabat, Pavel Moors, Eddy J. |
| author2Str |
Elbers, Jan A. Von Randow, Celso Araüjo, Alessandro Carioca de Oliveira, Paulo J.C. Culf, Alistair D. Manzi, Antônio Ocimar Nobre, Antônio Donato Kabat, Pavel Moors, Eddy J. |
| title |
The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| title_short |
The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| title_full |
The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| title_fullStr |
The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| title_full_unstemmed |
The robustness of eddy correlation fluxes for Amazon rain forest conditions |
| title_sort |
robustness of eddy correlation fluxes for amazon rain forest conditions |
| publisher |
Ecological Applications |
| publishDate |
2020 |
| url |
https://repositorio.inpa.gov.br/handle/1/18904 |
| _version_ |
1787142773718122496 |
| score |
11.755432 |