Abstract

Authors

Yasuda, Y., Ohtani, Y., Watanabe, T., Okano, M., Yokota, T., Liang, N., Tang, Y., Rahim Nik, A., Tani, M., Okuda, T.

Year

2003

Title

Measurement of CO₂ flux above a tropical rain forest at Pasoh in Peninsular Malaysia

Journal

Agricultural and forest meteorology

Volume

114(3-4)

Page

235-244

DOI

10.1016/S0168-1923(02)00198-3

Keywords

CO₂ flux; Eddy-covariance, Net ecosystem CO₂ exchange, Tropical rain forest, Southeast Asia

URL

http://www.sciencedirect.com/science

Abstract

This paper reports on the results of a short-term observation of CO₂ flux above a tropical forest at Pasoh in Peninsular Malaysia, using the eddy covariance method with a closed-path CO₂ analyzer, in March 1998. CO₂ concentration profiles above and in a canopy were also measured. In the daytime, the time series of fluctuations in CO₂ concentration above the forest drew the ramp pattern with a period of 2 min. This suggests that large-scale turbulent motions contribute to CO₂ flux in the daytime. We obtained data on the CO₂ flux for 6 days and CO₂ storage flux under the flux measurement level for 3 days in this observation. The values of the CO₂ flux fell within -1.0 to 0.5 mg CO₂ m^-2 s^-1. Net ecosystem CO₂ exchange (NEE) was estimated as the sum of the CO₂ flux and the CO₂ storage flux. Compared with the CO₂ flux, the CO₂ storage flux was relatively large in the early morning and the nighttime, therefore, the storage flux became important to estimate the NEE in those periods. The daily values of the NEE ranged from -2.08 to -2.74 g C m^-2 per day. The results suggest that this tropical forest was a CO₂ sink during the period. Although we tired to calculate the mass flow component proposed by Lee [Agric. For. Meteorol. 91 (1998) 39], the magnitudes of the mass flow obtained here were, from 5.20 to 12.55 g C m^-2 per day, much larger than the magnitudes of the NEE.

Site

PSO

Remarks

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