Partitioning Eddy-Covariance Methane Fluxes from a Shallow Lake into Diffusive and Ebullitive Fluxes
Partitioning Eddy-Covariance Methane Fluxes from a Shallow Lake into Diffusive and Ebullitive Fluxes
复制标题
将浅湖中的涡相关甲烷通量划分为扩散通量和沸腾通量
DOI：
10.1007/s10546-018-0383-1
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发表时间：
2018
影响因子：
4.3
通讯作者：
Iizuka Kotaro
中科院分区：
文献类型：
--
作者：
Iwata Hiroki;Hirata Ryuichi;Takahashi Yoshiyuki;Miyabara Yuichi;Itoh Masayuki;Iizuka Kotaro
众所周知，甲烷()通过扩散和沸腾(即气泡排放)等过程从湖泊排放到大气中。我们发展了一种实用的方法，将浅水湖泊的涡旋协变通量划分为扩散通量和沸腾通量，该方法基于浓度与其他参考标量(如气温或水汽浓度)在小波时间尺度域中的局部标量相似性，假设相似和不同的波动分量分别与扩散通量和沸腾通量有关。我们的方法被应用于在中纬度浅水湖获得的大约两周的数据。分割后的扩散通量与风速有良好的物理关系，支持了该方法的有效性。对于来自稳定气泡排放区域的流量，扩散通量与总通量的比率通常为0.11，而在其他情况下为0.36。需要使用更大的数据集和来自其他湖泊的数据进行进一步验证。该方法可以很容易地应用于历史数据，因为它只需要10赫兹的浓度数据和其他参考标量，以及一个经验参数。
Methane () is known to be emitted from lakes to the atmosphere via processes such as diffusion and ebullition (i.e., bubble emission). We developed a practical method for partitioning eddy-covariancefluxes from a shallow lake into diffusive and ebullitive fluxes using a wavelet analysis based on local scalar similarity between theconcentration and other reference scalars, such as the air temperature or water vapour concentration, in the wavelet time-scale domain, with the hypothesis that similar and dissimilar fluctuation components are related to diffusive and ebullitivefluxes, respectively. Our method is applied to approximately two weeks of data obtained at a shallow mid-latitude lake. The partitioned diffusive flux has a physically sound relationship with wind speed, supporting the validity of the method. The ratio of the diffusive flux to the total flux is typically 0.11 with flow from an area of steady bubble emission, but otherwise 0.36. Further validation is required using a larger dataset and data from other lakes. The proposed method can be easily applied to historical data because it requires only 10-Hz data ofconcentration and other reference scalars, along with an empirical parameter.