Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa

Onalenna Gwate, Sukhmani K. Mantel, Andiswa Finca, Lesley A. Gibson, Zahn Munch

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

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    Abstract

    Determining water and carbon fluxes over a vegetated surface is important in a context of global environmental changes and the fluxes help in understanding ecosystem functioning. Pursuant to this, the study measured evapotranspiration (ET) using an eddy covariance (EC) system installed over an intact example of the Albany Thicket (AT) vegetation in the Eastern Cape, South Africa. Environmental constraints to ET were also assessed by examining the response of ET to biotic and abiotic factors. The EC system comprised of an open path Infrared Gas Analyser and Sonic anemometer and an attendant weather station to measure bi-meteorological variables. Post processing of eddy covariance data was conducted using EddyPro software. Quality assessment of fluxes was also performed and rejected and missing data were filled using the method of mean diurnal variations (MDV). Much of the variation in ET was accounted for by the leaf area index (LAI, p < 0.001, 41%) and soil moisture content (SWC, p < 0.001, 32%). Total measured ET during the experiment was greater than total rainfall received owing to the high water storage capacity of the vegetation and the possibility of vegetation accessing ground water. Most of the net radiation was consumed by sensible heat flux and this means that ET in the area is essentially water limited since abundant energy was available to drive turbulent transfers of energy. Understanding the environmental constraints to ET is crucial in predicting the ecosystem response to environmental forces such as climate change.
    Original languageEnglish
    Title of host publicationProc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII
    EditorsChristopher M. U. Neale, Antonino Maltese
    PublisherSPIE
    Number of pages20
    Volume9998
    DOIs
    Publication statusPublished - 25 Oct 2016

    Fingerprint

    eddy covariance
    evapotranspiration
    environmental constraint
    leaf area index
    vegetation
    ecosystem response
    biotic factor
    anemometer
    net radiation
    sensible heat flux
    weather station
    carbon flux
    measuring
    Africa
    water storage
    diurnal variation
    energy
    moisture content
    environmental change
    soil moisture

    Keywords

    • evapotranspiration
    • covariance system
    • ecosystem
    • climate change

    Cite this

    Gwate, O., Mantel, S. K., Finca, A., Gibson, L. A., & Munch, Z. (2016). Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa. In C. M. U. Neale, & A. Maltese (Eds.), Proc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII (Vol. 9998). SPIE. https://doi.org/10.1117/12.2245426
    Gwate, Onalenna ; Mantel, Sukhmani K. ; Finca, Andiswa ; Gibson, Lesley A. ; Munch, Zahn. / Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa. Proc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII. editor / Christopher M. U. Neale ; Antonino Maltese. Vol. 9998 SPIE, 2016.
    @inproceedings{48f5d3d96e6c4c16a294ea5f31a2559f,
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    abstract = "Determining water and carbon fluxes over a vegetated surface is important in a context of global environmental changes and the fluxes help in understanding ecosystem functioning. Pursuant to this, the study measured evapotranspiration (ET) using an eddy covariance (EC) system installed over an intact example of the Albany Thicket (AT) vegetation in the Eastern Cape, South Africa. Environmental constraints to ET were also assessed by examining the response of ET to biotic and abiotic factors. The EC system comprised of an open path Infrared Gas Analyser and Sonic anemometer and an attendant weather station to measure bi-meteorological variables. Post processing of eddy covariance data was conducted using EddyPro software. Quality assessment of fluxes was also performed and rejected and missing data were filled using the method of mean diurnal variations (MDV). Much of the variation in ET was accounted for by the leaf area index (LAI, p < 0.001, 41{\%}) and soil moisture content (SWC, p < 0.001, 32{\%}). Total measured ET during the experiment was greater than total rainfall received owing to the high water storage capacity of the vegetation and the possibility of vegetation accessing ground water. Most of the net radiation was consumed by sensible heat flux and this means that ET in the area is essentially water limited since abundant energy was available to drive turbulent transfers of energy. Understanding the environmental constraints to ET is crucial in predicting the ecosystem response to environmental forces such as climate change.",
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    author = "Onalenna Gwate and Mantel, {Sukhmani K.} and Andiswa Finca and Gibson, {Lesley A.} and Zahn Munch",
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    Gwate, O, Mantel, SK, Finca, A, Gibson, LA & Munch, Z 2016, Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa. in CMU Neale & A Maltese (eds), Proc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII. vol. 9998, SPIE. https://doi.org/10.1117/12.2245426

    Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa. / Gwate, Onalenna; Mantel, Sukhmani K.; Finca, Andiswa; Gibson, Lesley A.; Munch, Zahn.

    Proc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII. ed. / Christopher M. U. Neale; Antonino Maltese. Vol. 9998 SPIE, 2016.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

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    AU - Mantel, Sukhmani K.

    AU - Finca, Andiswa

    AU - Gibson, Lesley A.

    AU - Munch, Zahn

    N1 - AAM: uploaded 12-1-17; no embargo (see http://spie.org/publications/journals/guidelines-for-authors)

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    N2 - Determining water and carbon fluxes over a vegetated surface is important in a context of global environmental changes and the fluxes help in understanding ecosystem functioning. Pursuant to this, the study measured evapotranspiration (ET) using an eddy covariance (EC) system installed over an intact example of the Albany Thicket (AT) vegetation in the Eastern Cape, South Africa. Environmental constraints to ET were also assessed by examining the response of ET to biotic and abiotic factors. The EC system comprised of an open path Infrared Gas Analyser and Sonic anemometer and an attendant weather station to measure bi-meteorological variables. Post processing of eddy covariance data was conducted using EddyPro software. Quality assessment of fluxes was also performed and rejected and missing data were filled using the method of mean diurnal variations (MDV). Much of the variation in ET was accounted for by the leaf area index (LAI, p < 0.001, 41%) and soil moisture content (SWC, p < 0.001, 32%). Total measured ET during the experiment was greater than total rainfall received owing to the high water storage capacity of the vegetation and the possibility of vegetation accessing ground water. Most of the net radiation was consumed by sensible heat flux and this means that ET in the area is essentially water limited since abundant energy was available to drive turbulent transfers of energy. Understanding the environmental constraints to ET is crucial in predicting the ecosystem response to environmental forces such as climate change.

    AB - Determining water and carbon fluxes over a vegetated surface is important in a context of global environmental changes and the fluxes help in understanding ecosystem functioning. Pursuant to this, the study measured evapotranspiration (ET) using an eddy covariance (EC) system installed over an intact example of the Albany Thicket (AT) vegetation in the Eastern Cape, South Africa. Environmental constraints to ET were also assessed by examining the response of ET to biotic and abiotic factors. The EC system comprised of an open path Infrared Gas Analyser and Sonic anemometer and an attendant weather station to measure bi-meteorological variables. Post processing of eddy covariance data was conducted using EddyPro software. Quality assessment of fluxes was also performed and rejected and missing data were filled using the method of mean diurnal variations (MDV). Much of the variation in ET was accounted for by the leaf area index (LAI, p < 0.001, 41%) and soil moisture content (SWC, p < 0.001, 32%). Total measured ET during the experiment was greater than total rainfall received owing to the high water storage capacity of the vegetation and the possibility of vegetation accessing ground water. Most of the net radiation was consumed by sensible heat flux and this means that ET in the area is essentially water limited since abundant energy was available to drive turbulent transfers of energy. Understanding the environmental constraints to ET is crucial in predicting the ecosystem response to environmental forces such as climate change.

    KW - evapotranspiration

    KW - covariance system

    KW - ecosystem

    KW - climate change

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    Gwate O, Mantel SK, Finca A, Gibson LA, Munch Z. Measuring evapotranspiration using an eddy covariance system over the Albany Thicket of the Eastern Cape, South Africa. In Neale CMU, Maltese A, editors, Proc. SPIE 9998, Remote Sensing for Agriculture, Ecosystems, and Hydrology XVIII. Vol. 9998. SPIE. 2016 https://doi.org/10.1117/12.2245426