Adjustment of annual NEE and ET for the open-path IRGA self-heating correction: Magnitude and approximation over a range of climate

Autor: Cristina Gimeno, V. Resco, María José Sanz, George Burba, B.R. Reverter, Arnaud Carrara, Penélope Serrano-Ortiz, A. Were, Francisco Domingo, Enrique P. Sánchez-Cañete, A. Fernández, Andrew S. Kowalski
Jazyk: angličtina
Rok vydání: 2011
Předmět:
Zdroj: Agricultural and Forest Meteorology
ISSN: 0168-1923
DOI: 10.1016/j.agrformet.2011.06.001
Popis: a b s t r a c t The self-heating correction is known to modify open-path eddy covariance estimates of net ecosystem CO2 exchange, typically towards reduced uptake or enhanced emissions, but with a magnitude hereto- fore not generally documented. We assess the magnitude of this correction to be of order 1 mol m−2 s−1 (daytime) for half-hourly fluxes and consistently over 100 g C m −2 for annual integrations, across a tower network (CARBORED-ES) spanning climate zones from Mediterranean temperate to cool alpine. We fur- thermore examine the sensitivity of the correction to its determining factors. Due to significant diurnal variation, the means of discriminating day versus night can lead to differences of up to several tens of g C m−2 year−1. Since its principal determinants - temperature and wind speed - do not include gas flux data, the annual correction can be estimated using only meteorological data so as to avoid uncertainties introduced when filling gaps in flux data. For fast retro-correction of annual integrations published prior to the recognition of this instrument surface heating effect, the annual impact can be roughly approxi- mated to within 12 g C m−2 year−1 by a linear function of mean annual temperature. These determinations highlight the need for the flux community to reach a consensus regarding the need for and the specific form of this correction. © 2011 Elsevier B.V. All rights reserved.
Databáze: OpenAIRE
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