Estimation of the storage and advection effects on H 2 O and CO 2 exchanges in a hilly KoFlux forest catchment

Jinkyu Hong, Joon Kim, Dongho Lee, Jong Hwan Lim

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We investigated the budget equations of H 2 O and CO 2 exchanges in a hilly KoFlux forest catchment. This site is characterized by a rolling terrain and mountain-valley circulations. The field measurements included two-level eddy-covariance (at 20 and 40 m) and H 2 O/CO 2 concentration profile systems on a single tower. To properly assess the vertical wind speed, we applied a planar fit rotation with atmospheric stabilities and wind directions. As atmospheric stability changed, the planar fit rotation gave different aspect slopes, which impacted on the estimation of vertical advection. Horizontal advection was estimated using a simple assumption of the quadratic profile within a forest canopy. Our analysis shows that the contributions of advective components were different not only between the two levels but also between CO 2 and H 2 O. At 40 m, the vertical and horizontal advection canceled each other out and therefore the turbulent eddy flux alone can be used for net ecosystem exchanges within 10% uncertainty. Near the canopy top (at 20 m), however, vertical advection should be taken into account for CO 2 . Also, even in windy conditions, advective fluxes were substantial. Well-calibrated multi-level eddy-covariance measurements along with profile measurement may provide useful insights for estimating the magnitude of advective fluxes over heterogeneous land surfaces.

Original languageEnglish
Article numberW01426
JournalWater Resources Research
Volume44
Issue number1
DOIs
Publication statusPublished - 2008 Jan 1

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advection
catchment
eddy covariance
net ecosystem exchange
forest canopy
wind direction
land surface
eddy
wind velocity
canopy
valley
mountain
effect

All Science Journal Classification (ASJC) codes

  • Water Science and Technology

Cite this

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abstract = "We investigated the budget equations of H 2 O and CO 2 exchanges in a hilly KoFlux forest catchment. This site is characterized by a rolling terrain and mountain-valley circulations. The field measurements included two-level eddy-covariance (at 20 and 40 m) and H 2 O/CO 2 concentration profile systems on a single tower. To properly assess the vertical wind speed, we applied a planar fit rotation with atmospheric stabilities and wind directions. As atmospheric stability changed, the planar fit rotation gave different aspect slopes, which impacted on the estimation of vertical advection. Horizontal advection was estimated using a simple assumption of the quadratic profile within a forest canopy. Our analysis shows that the contributions of advective components were different not only between the two levels but also between CO 2 and H 2 O. At 40 m, the vertical and horizontal advection canceled each other out and therefore the turbulent eddy flux alone can be used for net ecosystem exchanges within 10{\%} uncertainty. Near the canopy top (at 20 m), however, vertical advection should be taken into account for CO 2 . Also, even in windy conditions, advective fluxes were substantial. Well-calibrated multi-level eddy-covariance measurements along with profile measurement may provide useful insights for estimating the magnitude of advective fluxes over heterogeneous land surfaces.",
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Estimation of the storage and advection effects on H 2 O and CO 2 exchanges in a hilly KoFlux forest catchment . / Hong, Jinkyu; Kim, Joon; Lee, Dongho; Lim, Jong Hwan.

In: Water Resources Research, Vol. 44, No. 1, W01426, 01.01.2008.

Research output: Contribution to journalArticle

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