Open AccessDiurnal and vertical variability of the sensible heat and carbon dioxide budgets in the atmospheric surface layer
Author(s) -
CassoTorralba Pau,
VilàGuerau de Arellano Jordi,
Bosveld Fred,
Soler Maria Rosa,
Vermeulen Alex,
Werner Cindy,
Moors Eddy
Publication year - 2008
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jd009583
Subject(s) - advection , sensible heat , atmospheric sciences , environmental science , turbulence , carbon dioxide , flux (metallurgy) , mixed layer , daytime , potential temperature , heat flux , divergence (linguistics) , climatology , meteorology , heat transfer , mechanics , physics , geology , thermodynamics , chemistry , linguistics , philosophy , organic chemistry
The diurnal and vertical variability of heat and carbon dioxide (CO 2 ) in the atmospheric surface layer are studied by analyzing measurements from a 213 m tower in Cabauw (Netherlands). Observations of thermodynamic variables and CO 2 mixing ratio as well as vertical profiles of the turbulent fluxes are used to retrieve the contribution of the budget terms in the scalar conservation equation. On the basis of the daytime evolution of turbulent fluxes, we calculate the budget terms by assuming that turbulent fluxes follow a linear profile with height. This assumption is carefully tested and the deviation from linearity is quantified. The budget calculation allows us to assess the importance of advection of heat and CO 2 during day hours for three selected days. It is found that, under nonadvective conditions, the diurnal variability of temperature and CO 2 is well reproduced from the flux divergence measurements. Consequently, the vertical transport due to the turbulent flux plays a major role in the daytime evolution of both scalars and the advection is a relatively small contribution. During the analyzed days with a strong contribution of advection of either heat or carbon dioxide, the flux divergence is still an important contribution to the budget. For heat, the quantification of the advection contribution is in close agreement with results from a numerical model. For carbon dioxide, we qualitatively corroborate the results with a Lagrangian transport model. Our estimation of advection is compared with traditional estimations based on the Net Ecosystem‐atmosphere Exchange (NEE).