Automated Exponential Feedback Weighting method for subtraction of heat losses from sap flow measured by the trunk heat balance method

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

Automated Exponential Feedback Weighting method for subtraction of heat losses from sap flow measured by the trunk heat balance method

Popis výsledku v původním jazyce

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 &apos;baseline&apos;) 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 &apos;Exponential Feedback Weighting method&apos;. 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.

Název v anglickém jazyce

Automated Exponential Feedback Weighting method for subtraction of heat losses from sap flow measured by the trunk heat balance method

Popis výsledku anglicky

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 &apos;baseline&apos;) 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 &apos;Exponential Feedback Weighting method&apos;. 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.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

10611 - Plant sciences, botany

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Acta Horticulturae 1300

ISBN

978-94-6261-298-3

ISSN

0567-7572

e-ISSN

2406-6168

Počet stran výsledku

8

Strana od-do

81-88

Název nakladatele

International Society for Horticultural Science (ISHS)

Místo vydání

Leuven

Místo konání akce

Hyytiälä

Datum konání akce

7. 10. 2019

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000711432900011