TY - JOUR
T1 - Identifying CO2 advection on a hill slope using information flow
AU - Kang, Minseok
AU - Ruddell, Benjamin L.
AU - Cho, Chunho
AU - Chun, Junghwa
AU - Kim, Joon
N1 - Funding Information:
This work was supported by the Korea Meteorological Administration Research and Development Program under Grant KMIPA 2015-2023 , and Weather Information Service Engine (WISE) project, KMA-2012-0001-A . Dr. Benjamin L. Ruddell’s contribution to this research was supported by the National Science Foundation under Grant No. EF-1241960 . We thank Hyojung Kwon, Jinkyu Hong, Jaeill Yoo, Bindu Malla Thakuri, Juyeol Yun, Boeun Choi, and Je-woo Hong for their helpful support of the data collection and other logistics. The findings are those of the authors, and not necessarily the funding agencies or broader team members.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2017/1/15
Y1 - 2017/1/15
N2 - In hilly terrain affected by drainage flow, the horizontal advection of CO2 makes it difficult to accurately observe the net ecosystem exchange of CO2 by the eddy covariance technique. Downslope drainage can result in an overestimation of respiration at the bottom of a hill slope and an underestimation at the top, resulting in discrepancies among different flux corrections using filters based on the friction velocity, light response curve, and timing of advection. Vertical profiles of the CO2 concentration from the ground to above the canopy were measured along with above-canopy EC flux measurements at the top and bottom of a hill slope at the Gwangneung KoFlux sites from 2008 to 2010. To infer the timing, direction, temporal scale, and structure of CO2 advection from uphill to downhill, we constructed an information flow dynamical process network (DPN) based on the observed multi-level CO2 concentrations. A site-specific quality control filter was developed to eliminate data strongly affected by CO2 advection, which identifies the observations when strong downslope information flow exists in the DPN. This site-specific filter considerably reduced the discrepancies among different traditional flux corrections. This research provides a method for the general characterization of advection using information flow, and application of the method as a site-specific filter for eddy covariance observations in hilly and complex terrain.
AB - In hilly terrain affected by drainage flow, the horizontal advection of CO2 makes it difficult to accurately observe the net ecosystem exchange of CO2 by the eddy covariance technique. Downslope drainage can result in an overestimation of respiration at the bottom of a hill slope and an underestimation at the top, resulting in discrepancies among different flux corrections using filters based on the friction velocity, light response curve, and timing of advection. Vertical profiles of the CO2 concentration from the ground to above the canopy were measured along with above-canopy EC flux measurements at the top and bottom of a hill slope at the Gwangneung KoFlux sites from 2008 to 2010. To infer the timing, direction, temporal scale, and structure of CO2 advection from uphill to downhill, we constructed an information flow dynamical process network (DPN) based on the observed multi-level CO2 concentrations. A site-specific quality control filter was developed to eliminate data strongly affected by CO2 advection, which identifies the observations when strong downslope information flow exists in the DPN. This site-specific filter considerably reduced the discrepancies among different traditional flux corrections. This research provides a method for the general characterization of advection using information flow, and application of the method as a site-specific filter for eddy covariance observations in hilly and complex terrain.
KW - CO advection
KW - Dynamical process network
KW - Eddy covariance measurement
KW - Forest hill slope
KW - Information flow
KW - Nighttime CO flux correction
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U2 - 10.1016/j.agrformet.2016.08.003
DO - 10.1016/j.agrformet.2016.08.003
M3 - Article
AN - SCOPUS:84985982589
SN - 0168-1923
VL - 232
SP - 265
EP - 278
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
ER -