Abstract

The performance of different detrending methods in removing the low-frequencycontribution to the calculation of turbulent fluxes is investigated. The detrending methodsare applied to the calculation of turbulent fluxes of different scalars (temperature, ultrafineparticle number concentration, carbon dioxide and water vapour concentration), collectedat two different measurement sites: one urban and one suburban. We test and compare theperformance of filtering methodologies frequently used in real-time and automated procedures(mean removal, linear detrending, running mean, autoregressive filter) with the resultsobtained from a reference method, which is a spectral filter based on the Fourier decompositionof the time series. In general, the largest differences are found in the comparison betweenthe reference and the mean-removal procedures. The linear detrending and running-meanprocedures produce comparable results, and turbulent-flux estimations in better agreementwith the reference procedure than those obtained with the mean-removal procedure. Thebest agreement between the running mean and the spectral filter is achieved with a timewindow of 15min at both sites. For all the variables studied, average fluxes calculated usingthe autoregressive filter are increasingly overestimated for a time constant ? compared withthat obtained using the spectral filter. The minimization of the difference between the twodetrending methods is achieved with a time constant of 120 s, with similar behaviour observedat both sites.

Autore Pugliese

• Donateo Antonio , Cava Daniela , Contini Daniele

Tutti gli autori

• Donateo A.; D.Cava; D.Contini

Titolo volume/Rivista

Boundary-layer meteorology

Anno di pubblicazione

2017

ISSN

1573-1472

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

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Settori ERC

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Codici ASJC

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