Measuring methane flux from irrigated rice fields by eddy covariance method using open-path gas analyzer

Alberto, Ma. Carmelita R.; Waßmann, Reiner; Buresh, R. J.; Quilty, James R.; Correa, Teodoro Q.; Sandro, Joseph M.; Centeno, Caesar Arloo R.

doi:10.1016/j.fcr.2014.02.008

Cited by 89 publications

(61 citation statements)

References 93 publications

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“…This CH 4 inversion system is much simpler than inversions of atmospheric CO 2 , because CO 2 has much more variability in surface fluxes due to fairly-balanced emissions and sinks with strong diurnal variation on top of the spatial heterogeneity. Recent studies have reported weak and contrasting diurnal variations in CH 4 fluxes, e.g., always sink (Wang et al, 2013) or always source (Alberto et al 2014), which are thus far ignored in modeling atmospheric CH 4 , to the best of our knowledge and in this study as well. A diurnal cycle of CH 4 emissions is, however, much weaker than that of CO 2 for which photosynthetic uptake during the daylight period is generally balanced by CO 2 released during respiration within 24 hours.…”

Section: Introductionmentioning

confidence: 89%

Regional Methane Emission Estimation Based on Observed Atmospheric Concentrations (2002-2012)

Patra

Saeki

Ishijima

et al. 2016

Journal of the Meteorological Society of Japan

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Section: Introductionmentioning

confidence: 89%

Regional Methane Emission Estimation Based on Observed Atmospheric Concentrations (2002-2012)

Patra

Saeki

Ishijima

et al. 2016

Journal of the Meteorological Society of Japan

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“…We chose these two methods for comparison because they continue to form the traditional analysis performed on eddy covariance and chamber measurements of F CH4 (for example, Alberto et al . [], Hendriks et al . [], Strachan et al .…”

Section: Methodsmentioning

confidence: 99%

Identifying scale‐emergent, nonlinear, asynchronous processes of wetland methane exchange

et al. 2016

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Methane (CH4) exchange in wetlands is complex, involving nonlinear asynchronous processes across diverse time scales. These processes and time scales are poorly characterized at the whole‐ecosystem level, yet are crucial for accurate representation of CH4 exchange in process models. We used a combination of wavelet analysis and information theory to analyze interactions between whole‐ecosystem CH4 flux and biophysical drivers in two restored wetlands of Northern California from hourly to seasonal time scales, explicitly questioning assumptions of linear, synchronous, single‐scale analysis. Although seasonal variability in CH4 exchange was dominantly and synchronously controlled by soil temperature, water table fluctuations, and plant activity were important synchronous and asynchronous controls at shorter time scales that propagated to the seasonal scale. Intermittent, subsurface water table decline promoted short‐term pulses of methane emission but ultimately decreased seasonal CH4 emission through subsequent inhibition after rewetting. Methane efflux also shared information with evapotranspiration from hourly to multiday scales and the strength and timing of hourly and diel interactions suggested the strong importance of internal gas transport in regulating short‐term emission. Traditional linear correlation analysis was generally capable of capturing the major diel and seasonal relationships, but mesoscale, asynchronous interactions and nonlinear, cross‐scale effects were unresolved yet important for a deeper understanding of methane flux dynamics. We encourage wider use of these methods to aid interpretation and modeling of long‐term continuous measurements of trace gas and energy exchange.

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“…Low power usage portable IRGAs that are capable of sensing methane have only been manufactured recently [ Kormann et al ., ]. This method is becoming more common, though many of the studies which utilize these sensors focus on rice paddies [ Alberto et al ., ; Hatala et al ., ], peatlands [ Baldocchi et al ., ; Frolking et al ., ; Hatala et al ., , ; Long et al ., ], tundra [ Dengel et al ., ; Sachs et al ., ], and mires [ Forbrich et al ., ; Hargreaves et al ., ]. Eddy covariance studies focusing on temperate freshwater wetlands are still rare.…”

Section: Introductionmentioning

confidence: 99%

Environmental drivers of methane fluxes from an urban temperate wetland park

et al. 2014

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Methane (CH 4 ) emissions were measured at the Wilma H. Schiermeier Olentangy River Wetland Research Park (ORWRP) over three summers and two winters using an eddy covariance system. We used an empirical model to determine the main environmental drivers of methane emissions. Methane emissions covary strongly with water vapor fluxes, CO 2 fluxes, and soil temperature. We adjust our models to account for the heterogeneous environment of the wetland by including the flux footprint distribution among different microsites as a predictive variable in the methane model. We used a forward linear stepwise model in combination with an Akaike information criteria-based model selection process and neural network modeling to determine which environmental variables are most effective in modeling methane emissions in our site. Different models and environmental variables best represented methane fluxes in the winter and summer and also during the day or night within each season. We parameterized an optimal empirical model for methane emissions from the ORWRP that is used for gap filling of site-level methane fluxes over 2 years. Some of the most effective variables for modeling methane were carbon, water vapor, and heat fluxes, all of which typically have the same data gaps as the time series of methane flux. In order to determine if these variables were useful for modeling methane despite the additional gap-filling error, we determined through an error propagation experiment that eddy covariance gap-filling models for methane may be best developed by including other gap-filled fluxes as predictors, despite the high level of shared gaps and subsequent gap-fill error propagation.

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Measuring methane flux from irrigated rice fields by eddy covariance method using open-path gas analyzer

Cited by 89 publications

References 93 publications

Regional Methane Emission Estimation Based on Observed Atmospheric Concentrations (2002-2012)

Regional Methane Emission Estimation Based on Observed Atmospheric Concentrations (2002-2012)

Identifying scale‐emergent, nonlinear, asynchronous processes of wetland methane exchange

Environmental drivers of methane fluxes from an urban temperate wetland park

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