Сибирский федеральный университет

Тип публикации: доклад, тезисы доклада, статья из сборника материалов конференций

Год издания: 2020

Идентификатор DOI: 10.17660/ActaHortic.2020.1300.11

Ключевые слова: baseline subtraction, heat losses, sap flow, trunk heat balance method

Аннотация: 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 users 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 the 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 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 were provided by the 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. © 2020 International Society for Horticultural Science. All rights reserved.

Журнал: Acta Horticulturae

Выпуск журнала: Vol. 1300

Номера страниц: 81-88

ISSN журнала: 05677572

Издатель: International Society for Horticultural Science

• Kučera J. (Environmental Measuring Systems, Brno, Czech Republic)
• Vanıćček R. (IVASOFT, Systems, Brno, Czech Republic)
• Urban J. (Environmental Measuring Systems, Brno, Czech Republic, Faculty of Forestry and Wood Technology, Mendel University in, Brno, Czech Republic, Siberian Federal University, Krasnoyarsk, Russian Federation)

• Scopus
• Ядро РИНЦ (eLIBRARY.RU)