Flux-Variance Method for Latent Heat and Carbon Dioxide Fluxes in Unstable Conditions |
| |
| Authors: | Xiaofeng Guo Hongsheng Zhang Xuhui Cai Ling Kang Tong Zhu Monique Y Leclerc |
| |
| Institution: | (1) Department of Atmospheric Science, School of Physics, Peking University, 100871 Beijing, People’s Republic of China;(2) Department of Environmental Sciences, Peking University, 100871 Beijing, People’s Republic of China;(3) Laboratory for Environmental Physics, The University of Georgia, Griffin, GA, USA |
| |
| Abstract: | Applied previously to momentum and heat fluxes, the present study extends the flux-variance method to latent heat and CO2 fluxes in unstable conditions. Scalar similarity is also examined among temperature (θ), water vapour (q), and CO2 (c). Temperature is adopted as the reference scalar, leading to two feasible strategies to estimate latent heat and CO2 fluxes: the first one relies on flux-variance similarity relations for scalars, while the second is based on the parameterization
of relative transport efficiency in terms of scalar correlation coefficient and a non-dimensional quantity. The relationship
between the θ-to-q transport efficiency (λ
θ
q
) and θ-q correlation coefficient (R
θ
q
) is used to describe the intermediate hydrological conditions. We also parameterize the θ-to-c transport efficiency (λ
θ
c
) as a function of the θ-c correlation coefficient (R
θ
c
) by introducing a new non-dimensional ratio (α). The flux-variance method is a viable technique for flux gap-filling, when turbulence measurements of wind velocity are
not available. It is worth noting that the extended method is not exempt from a correction for density effects when used for
estimating water or carbon exchange. |
| |
| Keywords: | Atmospheric surface layer CO2 flux Density effect correction Eddy-covariance method Flux-variance method Monin– Obukhov similarity theory |
| 本文献已被 SpringerLink 等数据库收录！ |
|
