Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes

Handle URI:
http://hdl.handle.net/10754/334521
Title:
Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes
Authors:
Boegh, E.; Houborg, Rasmus; Bienkowski, J.; Braban, C.F.; Dalgaard, T.; Van, Dijk, N.; Dragosits, U.; Holmes, E.; Magliulo, V.; Schelde, K.; Di, Tommasi, P.; Vitale, L.; Theobald, M.R.; Cellier, P.; Sutton, M.A.
Abstract:
Leaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and play a significant role in the global cycles of carbon, nitrogen and water. The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, the Netherlands and Italy. REGFLEC (REGularized canopy reFLECtance) is an advanced image-based inverse canopy radiative transfer modelling system which has shown proficiency for regional mapping of leaf area index (LAI) and leaf chlorophyll (CHLl) using remote sensing data. In this study, high spatial resolution (10-20 m) remote sensing images acquired from the multispectral sensors aboard the SPOT (Satellite For Observation of Earth) satellites were used to assess the capability of REGFLEC for mapping spatial variations in LAI, CHLland the relation to leaf nitrogen (Nl) data in five diverse European agricultural landscapes. REGFLEC is based on physical laws and includes an automatic model parameterization scheme which makes the tool independent of field data for model calibration. In this study, REGFLEC performance was evaluated using LAI measurements and non-destructive measurements (using a SPAD meter) of leaf-scale CHLl and Nl concentrations in 93 fields representing crop- and grasslands of the five landscapes. Furthermore, empirical relationships between field measurements (LAI, CHLl and Nl and five spectral vegetation indices (the Normalized Difference Vegetation Index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green chlorophyll index) were used to assess field data coherence and to serve as a comparison basis for assessing REGFLEC model performance. The field measurements showed strong vertical CHLl gradient profiles in 26% of fields which affected REGFLEC performance as well as the relationships between spectral vegetation indices (SVIs) and field measurements. When the range of surface types increased, the REGFLEC results were in better agreement with field data than the empirical SVI regression models. Selecting only homogeneous canopies with uniform CHLl distributions as reference data for evaluation, REGFLEC was able to explain 69% of LAI observations (rmse Combining double low line 0.76), 46% of measured canopy chlorophyll contents (rmse Combining double low line 719 mg m-2) and 51% of measured canopy nitrogen contents (rmse Combining double low line 2.7 g m-2). Better results were obtained for individual landscapes, except for Italy, where REGFLEC performed poorly due to a lack of dense vegetation canopies at the time of satellite recording. Presence of vegetation is needed to parameterize the REGFLEC model. Combining REGFLEC- and SVI-based model results to minimize errors for a "snap-shot" assessment of total leaf nitrogen pools in the five landscapes, results varied from 0.6 to 4.0 t km-2. Differences in leaf nitrogen pools between landscapes are attributed to seasonal variations, extents of agricultural area, species variations, and spatial variations in nutrient availability. In order to facilitate a substantial assessment of variations in Nl pools and their relation to landscape based nitrogen and carbon cycling processes, time series of satellite data are needed. The upcoming Sentinel-2 satellite mission will provide new multiple narrowband data opportunities at high spatiooral resolution which are expected to further improve remote sensing capabilities for mapping LAI, CHLl and Nl. Author(s) 2013. CC Attribution 3.0 License.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC)
Citation:
Boegh E, Houborg R, Bienkowski J, Braban CF, Dalgaard T, et al. (2013) Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes. Biogeosciences 10: 6279-6307. doi:10.5194/bg-10-6279-2013.
Publisher:
Copernicus GmbH
Journal:
Biogeosciences
Issue Date:
7-Oct-2013
DOI:
10.5194/bg-10-6279-2013
Type:
Article
ISSN:
17264170
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorBoegh, E.en
dc.contributor.authorHouborg, Rasmusen
dc.contributor.authorBienkowski, J.en
dc.contributor.authorBraban, C.F.en
dc.contributor.authorDalgaard, T.en
dc.contributor.authorVan, Dijk, N.en
dc.contributor.authorDragosits, U.en
dc.contributor.authorHolmes, E.en
dc.contributor.authorMagliulo, V.en
dc.contributor.authorSchelde, K.en
dc.contributor.authorDi, Tommasi, P.en
dc.contributor.authorVitale, L.en
dc.contributor.authorTheobald, M.R.en
dc.contributor.authorCellier, P.en
dc.contributor.authorSutton, M.A.en
dc.date.accessioned2014-11-11T14:28:13Z-
dc.date.available2014-11-11T14:28:13Z-
dc.date.issued2013-10-07en
dc.identifier.citationBoegh E, Houborg R, Bienkowski J, Braban CF, Dalgaard T, et al. (2013) Remote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapes. Biogeosciences 10: 6279-6307. doi:10.5194/bg-10-6279-2013.en
dc.identifier.issn17264170en
dc.identifier.doi10.5194/bg-10-6279-2013en
dc.identifier.urihttp://hdl.handle.net/10754/334521en
dc.description.abstractLeaf nitrogen and leaf surface area influence the exchange of gases between terrestrial ecosystems and the atmosphere, and play a significant role in the global cycles of carbon, nitrogen and water. The purpose of this study is to use field-based and satellite remote-sensing-based methods to assess leaf nitrogen pools in five diverse European agricultural landscapes located in Denmark, Scotland (United Kingdom), Poland, the Netherlands and Italy. REGFLEC (REGularized canopy reFLECtance) is an advanced image-based inverse canopy radiative transfer modelling system which has shown proficiency for regional mapping of leaf area index (LAI) and leaf chlorophyll (CHLl) using remote sensing data. In this study, high spatial resolution (10-20 m) remote sensing images acquired from the multispectral sensors aboard the SPOT (Satellite For Observation of Earth) satellites were used to assess the capability of REGFLEC for mapping spatial variations in LAI, CHLland the relation to leaf nitrogen (Nl) data in five diverse European agricultural landscapes. REGFLEC is based on physical laws and includes an automatic model parameterization scheme which makes the tool independent of field data for model calibration. In this study, REGFLEC performance was evaluated using LAI measurements and non-destructive measurements (using a SPAD meter) of leaf-scale CHLl and Nl concentrations in 93 fields representing crop- and grasslands of the five landscapes. Furthermore, empirical relationships between field measurements (LAI, CHLl and Nl and five spectral vegetation indices (the Normalized Difference Vegetation Index, the Simple Ratio, the Enhanced Vegetation Index-2, the Green Normalized Difference Vegetation Index, and the green chlorophyll index) were used to assess field data coherence and to serve as a comparison basis for assessing REGFLEC model performance. The field measurements showed strong vertical CHLl gradient profiles in 26% of fields which affected REGFLEC performance as well as the relationships between spectral vegetation indices (SVIs) and field measurements. When the range of surface types increased, the REGFLEC results were in better agreement with field data than the empirical SVI regression models. Selecting only homogeneous canopies with uniform CHLl distributions as reference data for evaluation, REGFLEC was able to explain 69% of LAI observations (rmse Combining double low line 0.76), 46% of measured canopy chlorophyll contents (rmse Combining double low line 719 mg m-2) and 51% of measured canopy nitrogen contents (rmse Combining double low line 2.7 g m-2). Better results were obtained for individual landscapes, except for Italy, where REGFLEC performed poorly due to a lack of dense vegetation canopies at the time of satellite recording. Presence of vegetation is needed to parameterize the REGFLEC model. Combining REGFLEC- and SVI-based model results to minimize errors for a "snap-shot" assessment of total leaf nitrogen pools in the five landscapes, results varied from 0.6 to 4.0 t km-2. Differences in leaf nitrogen pools between landscapes are attributed to seasonal variations, extents of agricultural area, species variations, and spatial variations in nutrient availability. In order to facilitate a substantial assessment of variations in Nl pools and their relation to landscape based nitrogen and carbon cycling processes, time series of satellite data are needed. The upcoming Sentinel-2 satellite mission will provide new multiple narrowband data opportunities at high spatiooral resolution which are expected to further improve remote sensing capabilities for mapping LAI, CHLl and Nl. Author(s) 2013. CC Attribution 3.0 License.en
dc.language.isoenen
dc.publisherCopernicus GmbHen
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/en
dc.subjectagricultural landen
dc.subjectatmosphere-biosphere interactionen
dc.subjectbiogeochemistryen
dc.subjectcanopy reflectanceen
dc.subjectchlorophyllen
dc.subjectgrasslanden
dc.subjectleaf area indexen
dc.subjectmappingen
dc.subjectNDVIen
dc.subjectnitrogenen
dc.subjectradiative transferen
dc.subjectremote sensingen
dc.subjectsatellite imageryen
dc.subjectsatellite missionen
dc.subjectspatial resolutionen
dc.subjectSPOTen
dc.subjectDenmarken
dc.subjectItalyen
dc.subjectNetherlandsen
dc.subjectPolanden
dc.subjectScotlanden
dc.subjectUnited Kingdomen
dc.titleRemote sensing of LAI, chlorophyll and leaf nitrogen pools of crop- and grasslands in five European landscapesen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalBiogeosciencesen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionRoskilde University, Dept. of Environmental, Social and Spatial Change, Roskilde, Denmarken
dc.contributor.institutionInstitute for Agricultural and Forest Environment, Polish Academy of Sciences, Poznan, Polanden
dc.contributor.institutionCentre for Ecology and Hydrology, Edinburgh Research Station, Penicuik, United Kingdomen
dc.contributor.institutionAarhus University, Dept of Agroecology, Tjele, Denmarken
dc.contributor.institutionCNR ISAFoM, Napoli, Italyen
dc.contributor.institutionTechnical University of Madrid, E. T. S. i Agronomos, Madrid, Spainen
dc.contributor.institutionINRA, UMR1091 Environnement et Grandes Cultures, Thiverval-Grignon, Franceen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorHouborg, Rasmusen
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