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Impact of nutrients on peatland GPP estimations using MODIS time series data

Schubert, Per LU ; Lund, Magnus LU ; Ström, Lena LU and Eklundh, Lars LU (2010) In Remote Sensing of Environment 114(10). p.2137-2145
Abstract
Time series of satellite sensor-derived data can be used in the light use efficiency (LUE) model for gross primary productivity (GPP). The LUE model and a closely related linear regression model were studied at an ombrotrophic peatland in southern Sweden. Eddy covariance and chamber GPP, incoming and reflected photosynthetic photon flux density (PPFD), field-measured spectral reflectance, and data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used in this study. The chamber and spectral reflectance measurements were made on four experimental treatments: unfertilized control (Ctrl). nitrogen fertilized (N), phosphorus fertilized (P), and nitrogen plus phosphorus fertilized (NP). For Ctrl, a strong linear relationship... (More)
Time series of satellite sensor-derived data can be used in the light use efficiency (LUE) model for gross primary productivity (GPP). The LUE model and a closely related linear regression model were studied at an ombrotrophic peatland in southern Sweden. Eddy covariance and chamber GPP, incoming and reflected photosynthetic photon flux density (PPFD), field-measured spectral reflectance, and data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used in this study. The chamber and spectral reflectance measurements were made on four experimental treatments: unfertilized control (Ctrl). nitrogen fertilized (N), phosphorus fertilized (P), and nitrogen plus phosphorus fertilized (NP). For Ctrl, a strong linear relationship was found between GPP and the photosynthetically active radiation absorbed by vegetation (APAR) (R-2=0.90). The slope coefficient (epsilon(s), where s stands for "slope") for the linear relationship between seasonal time series of GPP and the product of the normalized difference vegetation index (NDVI) and PPFD was used as a proxy for the light use efficiency factor (epsilon). There were differences in epsilon(s) depending on the treatments with a significant effect for N compared to Ctrl (ANOVA: p = 0.042, Tukey's: p <= 0.05). Also. epsilon(s) was linearly related to the cover degree of vascular plants (R-2= 0.66). As a sensitivity test, the regression coefficients (epsilon(s) and intercept) for each treatment were used to model time series of 16-day GPP from the product of MODIS NDVI and PPFD. Seasonal averages of GPP were calculated for 2005, 2006. and 2007, which resulted in up to 19% higher average GPP for the fertilization treatments compared to Ctrl. The main conclusion is that the LUE model and the regression model can be applied in peatlands but also that temporal and spatial changes in epsilon or the regression coefficients should be considered. (C) 2010 Elsevier Inc. All rights reserved. (Less)
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organization
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Contribution to journal
publication status
published
subject
keywords
Photosynthetic photon flux density (PPFD), Absorbed photosynthetically active radiation (APAR), Fraction of absorbed photosynthetically active radiation (FAPAR), Gross primary productivity (GPP), Light use efficiency (LUE), Moderate Resolution Imaging Spectroradiometer (MODIS), Normalized difference vegetation index (NDVI)
in
Remote Sensing of Environment
volume
114
issue
10
pages
2137 - 2145
publisher
Elsevier
external identifiers
  • wos:000281187400003
  • scopus:77955275766
ISSN
0034-4257
DOI
10.1016/j.rse.2010.04.018
project
BECC
language
English
LU publication?
yes
id
ca961709-b69c-4665-8b98-cb89d9d113b1 (old id 1672587)
alternative location
http://dx.doi.org/10.1016/j.rse.2010.04.018
date added to LUP
2010-09-23 13:28:15
date last changed
2018-05-29 10:00:54
@article{ca961709-b69c-4665-8b98-cb89d9d113b1,
  abstract     = {Time series of satellite sensor-derived data can be used in the light use efficiency (LUE) model for gross primary productivity (GPP). The LUE model and a closely related linear regression model were studied at an ombrotrophic peatland in southern Sweden. Eddy covariance and chamber GPP, incoming and reflected photosynthetic photon flux density (PPFD), field-measured spectral reflectance, and data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used in this study. The chamber and spectral reflectance measurements were made on four experimental treatments: unfertilized control (Ctrl). nitrogen fertilized (N), phosphorus fertilized (P), and nitrogen plus phosphorus fertilized (NP). For Ctrl, a strong linear relationship was found between GPP and the photosynthetically active radiation absorbed by vegetation (APAR) (R-2=0.90). The slope coefficient (epsilon(s), where s stands for "slope") for the linear relationship between seasonal time series of GPP and the product of the normalized difference vegetation index (NDVI) and PPFD was used as a proxy for the light use efficiency factor (epsilon). There were differences in epsilon(s) depending on the treatments with a significant effect for N compared to Ctrl (ANOVA: p = 0.042, Tukey's: p &lt;= 0.05). Also. epsilon(s) was linearly related to the cover degree of vascular plants (R-2= 0.66). As a sensitivity test, the regression coefficients (epsilon(s) and intercept) for each treatment were used to model time series of 16-day GPP from the product of MODIS NDVI and PPFD. Seasonal averages of GPP were calculated for 2005, 2006. and 2007, which resulted in up to 19% higher average GPP for the fertilization treatments compared to Ctrl. The main conclusion is that the LUE model and the regression model can be applied in peatlands but also that temporal and spatial changes in epsilon or the regression coefficients should be considered. (C) 2010 Elsevier Inc. All rights reserved.},
  author       = {Schubert, Per and Lund, Magnus and Ström, Lena and Eklundh, Lars},
  issn         = {0034-4257},
  keyword      = {Photosynthetic photon flux density (PPFD),Absorbed photosynthetically active radiation (APAR),Fraction of absorbed photosynthetically active radiation (FAPAR),Gross primary productivity (GPP),Light use efficiency (LUE),Moderate Resolution Imaging Spectroradiometer (MODIS),Normalized difference vegetation index (NDVI)},
  language     = {eng},
  number       = {10},
  pages        = {2137--2145},
  publisher    = {Elsevier},
  series       = {Remote Sensing of Environment},
  title        = {Impact of nutrients on peatland GPP estimations using MODIS time series data},
  url          = {http://dx.doi.org/10.1016/j.rse.2010.04.018},
  volume       = {114},
  year         = {2010},
}