2016年6月
Does measuring azimuthal variations in sap flux lead to more reliable stand transpiration estimates?
HYDROLOGICAL PROCESSES
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- 巻
- 30
- 号
- 13
- 開始ページ
- 2129
- 終了ページ
- 2137
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1002/hyp.10780
- 出版者・発行元
- WILEY-BLACKWELL
Stand transpiration (E) estimated using the sap-flux method includes uncertainty induced by variations in sap flux (F) within a tree (i.e. radial and azimuthal variations) and those between trees. Unlike radial variations, azimuthal variations are not particularly systematic (i.e. higher/lower F is not always recorded for a specific direction). Here, we present a theoretical framework to address the question on how to allocate a limited number of sensors to minimize uncertainty in E estimates. Specifically, we compare uncertainty in E estimates for two cases: (1) measuring F for two or more directions to cover azimuthal variations in F and (2) measuring F for one direction to cover between-tree variations in F. The framework formulates the variation in the probability density function for E (sigma(E)) based on F recorded in m different azimuthal directions (e.g. north, east, south and west). This formula allows us to determine the m value that minimizes sigma(E). This study applied the framework to F data recorded for a 55-year-old Cryptomeria japonica stand. sigma(E) for m=1 was found to be less than the values for m=2, 3 and 4. Our results suggest that measuring F for one azimuthal direction provides more reliable E estimates than measuring F for two or more azimuthal directions for this stand, given a limited number of sensors. Application of this framework to other datasets helps us decide how to allocate sensors most effectively. Copyright (c) 2016 John Wiley & Sons, Ltd.
- リンク情報
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- DOI
- https://doi.org/10.1002/hyp.10780
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000379739600012&DestApp=WOS_CPL
- URL
- https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84977746141&origin=inward
- ID情報
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- DOI : 10.1002/hyp.10780
- ISSN : 0885-6087
- eISSN : 1099-1085
- Web of Science ID : WOS:000379739600012