Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations

Handle URI:
http://hdl.handle.net/10754/346996
Title:
Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations
Authors:
Schull, M. A.; Anderson, M. C.; Houborg, Rasmus; Gitelson, A.; Kustas, W. P.
Abstract:
Recent studies have shown that estimates of leaf chlorophyll content (Chl), defined as the combined mass of chlorophyll a and chlorophyll b per unit leaf area, can be useful for constraining estimates of canopy light use efficiency (LUE). Canopy LUE describes the amount of carbon assimilated by a vegetative canopy for a given amount of absorbed photosynthetically active radiation (APAR) and is a key parameter for modeling land-surface carbon fluxes. A carbon-enabled version of the remote-sensing-based two-source energy balance (TSEB) model simulates coupled canopy transpiration and carbon assimilation using an analytical sub-model of canopy resistance constrained by inputs of nominal LUE (βn), which is modulated within the model in response to varying conditions in light, humidity, ambient CO2 concentration, and temperature. Soil moisture constraints on water and carbon exchange are conveyed to the TSEB-LUE indirectly through thermal infrared measurements of land-surface temperature. We investigate the capability of using Chl estimates for capturing seasonal trends in the canopy βn from in situ measurements of Chl acquired in irrigated and rain-fed fields of soybean and maize near Mead, Nebraska. The results show that field-measured Chl is nonlinearly related to βn, with variability primarily related to phenological changes during early growth and senescence. Utilizing seasonally varying βn inputs based on an empirical relationship with in situ measured Chl resulted in improvements in carbon flux estimates from the TSEB model, while adjusting the partitioning of total water loss between plant transpiration and soil evaporation. The observed Chl-βn relationship provides a functional mechanism for integrating remotely sensed Chl into the TSEB model, with the potential for improved mapping of coupled carbon, water, and energy fluxes across vegetated landscapes.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC)
Citation:
Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations 2015, 12 (5):1511 Biogeosciences
Publisher:
European Geosciences Union
Journal:
Biogeosciences
Issue Date:
11-Mar-2015
DOI:
10.5194/bg-12-1511-2015; 10.5194/bgd-11-14133-2014
Type:
Article
ISSN:
1726-4189
Additional Links:
http://www.biogeosciences.net/12/1511/2015/; http://www.biogeosciences.net/12/1511/2015/bg-12-1511-2015-discussion.html
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorSchull, M. A.en
dc.contributor.authorAnderson, M. C.en
dc.contributor.authorHouborg, Rasmusen
dc.contributor.authorGitelson, A.en
dc.contributor.authorKustas, W. P.en
dc.date.accessioned2015-03-23T08:18:53Zen
dc.date.available2015-03-23T08:18:53Zen
dc.date.issued2015-03-11en
dc.identifier.citationThermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations 2015, 12 (5):1511 Biogeosciencesen
dc.identifier.issn1726-4189en
dc.identifier.doi10.5194/bg-12-1511-2015en
dc.identifier.doi10.5194/bgd-11-14133-2014en
dc.identifier.urihttp://hdl.handle.net/10754/346996en
dc.description.abstractRecent studies have shown that estimates of leaf chlorophyll content (Chl), defined as the combined mass of chlorophyll a and chlorophyll b per unit leaf area, can be useful for constraining estimates of canopy light use efficiency (LUE). Canopy LUE describes the amount of carbon assimilated by a vegetative canopy for a given amount of absorbed photosynthetically active radiation (APAR) and is a key parameter for modeling land-surface carbon fluxes. A carbon-enabled version of the remote-sensing-based two-source energy balance (TSEB) model simulates coupled canopy transpiration and carbon assimilation using an analytical sub-model of canopy resistance constrained by inputs of nominal LUE (βn), which is modulated within the model in response to varying conditions in light, humidity, ambient CO2 concentration, and temperature. Soil moisture constraints on water and carbon exchange are conveyed to the TSEB-LUE indirectly through thermal infrared measurements of land-surface temperature. We investigate the capability of using Chl estimates for capturing seasonal trends in the canopy βn from in situ measurements of Chl acquired in irrigated and rain-fed fields of soybean and maize near Mead, Nebraska. The results show that field-measured Chl is nonlinearly related to βn, with variability primarily related to phenological changes during early growth and senescence. Utilizing seasonally varying βn inputs based on an empirical relationship with in situ measured Chl resulted in improvements in carbon flux estimates from the TSEB model, while adjusting the partitioning of total water loss between plant transpiration and soil evaporation. The observed Chl-βn relationship provides a functional mechanism for integrating remotely sensed Chl into the TSEB model, with the potential for improved mapping of coupled carbon, water, and energy fluxes across vegetated landscapes.en
dc.publisherEuropean Geosciences Unionen
dc.relation.urlhttp://www.biogeosciences.net/12/1511/2015/en
dc.relation.urlhttp://www.biogeosciences.net/12/1511/2015/bg-12-1511-2015-discussion.htmlen
dc.rightsThis work is distributed under the Creative Commons Attribution 3.0 License.en
dc.titleThermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observationsen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalBiogeosciencesen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionUSDA-ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD, USAen
dc.contributor.institutionCenter for Advanced Land Management Information Technology (CALMIT), School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USAen
dc.contributor.institutionIsrael Institute of Technology, Haifa, Israelen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorHouborg, Rasmusen
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