Elsevier

Acta Ecologica Sinica

Volume 28, Issue 7, July 2008, Pages 3017-3026
Acta Ecologica Sinica

RESEARCH PAPER
Influences of error distributions of net ecosystem exchange on parameter estimation of a process-based terrestrial model: A case of broad-leaved Korean pine mixed forest in Changbaishan, China

https://doi.org/10.1016/S1872-2032(08)60065-7Get rights and content

Abstract

Model predictions can be improved by parameter estimation from measurements. It was assumed that measurement errors of net ecosystem exchange (NEE) of CO2 follow a normal distribution. However, recent studies have shown that errors in eddy covariance measurements closely follow a double exponential distribution. In this paper, we compared effects of different distributions of measurement errors of NEE data on parameter estimation. NEE measurements in the Changbaishan forest were assimilated into a process-based terrestrial ecosystem model. We used the Markov chain Monte Carlo method to derive probability density functions of estimated parameters. Our results showed that modeled annual total gross primary production (GPP) and ecosystem respiration (Re) using the normal error distribution were higher than those using the double exponential distribution by 61–86 gC m−2 a−1 and 107–116 gC m−2 a−1, respectively. As a result, modeled annual sum of NEE using the normal error distribution was lower by 29–47 gC m−2 a−1 than that using the double exponential error distribution. Especially, modeled daily NEE based on the normal distribution underestimated the strong carbon sink in the Changbaishan forest in the growing season. We concluded that types of measurement error distributions and corresponding cost functions can substantially influence the estimation of parameters and carbon fluxes.

Key Words

NEE
ecosystem model
parameter estimation
error distribution
Markov chain Monte Carlo method

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