Automated Exponential Feedback Weighting method for subtraction of heat losses from sap flow measured by the trunk heat balance method
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62156489%3A43410%2F20%3A43918027" target="_blank" >RIV/62156489:43410/20:43918027 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.17660/ActaHortic.2020.1300.11" target="_blank" >https://doi.org/10.17660/ActaHortic.2020.1300.11</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.17660/ActaHortic.2020.1300.11" target="_blank" >10.17660/ActaHortic.2020.1300.11</a>
Alternative languages
Result language
angličtina
Original language name
Automated Exponential Feedback Weighting method for subtraction of heat losses from sap flow measured by the trunk heat balance method
Original language description
Removal of heat losses from the measuring point is one of the crucial issues during processing of data from the sap flow sensors, including the trunk heat balance method (THB). Heat losses (here referred to as 'baseline') are usually estimated at the time of presumably no sap flow. Three main issues may decrease the accuracy of the estimation of baseline: (i) existing sap flow in the night, which did not stop due to ongoing night transpiration or xylem refilling, (ii) natural temperature gradients between heated and reference part of the measuring point, and (iii) long-time (i.e. seasonal) changes in the heat losses due to stem growth or changes in the stem heat conductivity. Therefore, neither the estimation of baseline each night, nor its estimation as a lowest value in a specific (i.e. 2-week period) provide the correct result. Experienced used may be able to estimate the baseline manually (taking into consideration i.e. vapor pressure deficit) but this is a subjective and lengthy approach. Here we present an automated baseline subtraction based on 'Exponential Feedback Weighting method'. This method considers the nighttime sap flow, but it also removes outliers due to natural temperature gradients. We compared various averaging intervals of this method for the removal of baseline, from one day (i.e. estimation at every night) to 28 days in a 1-day increments, estimation at the beginning and at the end of the season and manual subtraction by user (considering the weather data). Best results provided 5-days weighting average, which was closest to the manual subtraction, and also provided enough flexibility for changes in baseline due to changes in the stem heat conductance.
Czech name
—
Czech description
—
Classification
Type
D - Article in proceedings
CEP classification
—
OECD FORD branch
10611 - Plant sciences, botany
Result continuities
Project
—
Continuities
S - Specificky vyzkum na vysokych skolach
Others
Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Article name in the collection
Acta Horticulturae 1300
ISBN
978-94-6261-298-3
ISSN
0567-7572
e-ISSN
2406-6168
Number of pages
8
Pages from-to
81-88
Publisher name
International Society for Horticultural Science (ISHS)
Place of publication
Leuven
Event location
Hyytiälä
Event date
Oct 7, 2019
Type of event by nationality
WRD - Celosvětová akce
UT code for WoS article
000711432900011