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A new mass conservation approach to the study of CO2 advection in an alpine forest

Montagnani, L. and Manca, G. and Canepa, E. and Georgieva, E. and Acosta, M. and Feigenwinter, C. and Janous, D. and Kerschbaumer, G. and Lindroth, A. and Minach, L. and Minerbi, S. and Mölder, M. and Pavelka, M. and Seufert, G. and Zeri, M. and Ziegler, W.. (2009) A new mass conservation approach to the study of CO2 advection in an alpine forest. Journal of geophysical research. D, Atmospheres, 114 , D07306. p. 25.

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Official URL: http://edoc.unibas.ch/dok/A5259961

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Abstract

A new method is proposed for the computation of CO 2 Net Ecosystem Exchange(NEE) and its components in a forest ecosystem. Advective flux is estimated by takinginto account the air mass conservation principle. For this purpose, wind and dry airdensity values on the surface of the control volume are first corrected and then theadvective flux is estimated on the surface of the control volume. Turbulent flux is alsocomputed along the surface of the control volume while storage flux is computed insidethe volume. Additional characteristics of this method are that incompressibility of themean flow is not assumed a priori, and that vertical and horizontal advective fluxes are nottreated separately, but their sum is estimated directly. The methodology is applied toexperimental data collected with a three-dimensional scheme at the alpine site of Renonduring the Advex project (July 2005). The advection flux was found to be prevailingpositive at night and negative during the day, as was found in previous studies onadvection for the same site, but showed a lower scatter in half-hour calculated values. Wetested the effect of its summation on turbulent and storage fluxes to produce half-hourlyvalues of NEE. Nighttime NEE values were used in functional relations with soiltemperature, daytime values with PPFD. The effect of addition of the advectioncomponent was an increase in the values of parameters indicating ecosystem respiration,quantum yield, and photosynthetic capacity. The coefficient of correlation between NEEand environmental drivers increased.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Meteorologie, Klimatologie und Fernerkundung > Meteorologie (Parlow)
UniBasel Contributors:Feigenwinter, Christian
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:American Geophysical Union
ISSN:0148-0227
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:01 Dec 2017 10:20
Deposited On:22 Mar 2012 14:16

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