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Evaluating Water Controls on Vegetation Growth in the Semi-Arid Sahel Using Field and Earth Observation Data

Abdi, Abdulhakim LU ; Boke-Olén, Niklas LU ; Tenenbaum, David LU ; Tagesson, Torbern LU ; Cappelaere, Bernard and Ardö, Jonas LU (2017) In Remote Sensing 9(3).
Abstract
Water loss is a crucial factor for vegetation in the semi-arid Sahel region of Africa. Global satellite-driven estimates of plant CO2 uptake (gross primary productivity, GPP) have been found to not accurately account for Sahelian conditions, particularly the impact of canopy water stress. Here, we identify the main biophysical limitations that induce canopy water stress in Sahelian vegetation and evaluate the relationships between field data and Earth observation-derived spectral products for up-scaling GPP. We find that plant-available water and vapor pressure deficit together control the GPP of Sahelian vegetation through their impact on the greening and browning phases. Our results show that a multiple linear regression (MLR) GPP model... (More)
Water loss is a crucial factor for vegetation in the semi-arid Sahel region of Africa. Global satellite-driven estimates of plant CO2 uptake (gross primary productivity, GPP) have been found to not accurately account for Sahelian conditions, particularly the impact of canopy water stress. Here, we identify the main biophysical limitations that induce canopy water stress in Sahelian vegetation and evaluate the relationships between field data and Earth observation-derived spectral products for up-scaling GPP. We find that plant-available water and vapor pressure deficit together control the GPP of Sahelian vegetation through their impact on the greening and browning phases. Our results show that a multiple linear regression (MLR) GPP model that combines the enhanced vegetation index, land surface temperature, and the short-wave infrared reflectance (Band 7, 2105–2155 nm) of the moderate-resolution imaging spectroradiometer satellite sensor was able to explain between 88% and 96% of the variability of eddy covariance flux tower GPP at three Sahelian sites (overall = 89%). The MLR GPP model presented here is potentially scalable at a relatively high spatial and temporal resolution. Given the scarcity of field data on CO2 fluxes in the Sahel, this scalability is important due to the low number of flux towers in the region. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Sahel, Drought, gross pri, Earth observation, Plant available water, Soil moisture, Vapor pressure deficit, Plant stress, Greening, Browning
in
Remote Sensing
volume
9
issue
3
publisher
MDPI AG
external identifiers
  • scopus:85019370047
  • wos:000398720100107
ISSN
2072-4292
DOI
10.3390/rs9030294
language
English
LU publication?
yes
id
a420fc0b-0111-4f08-acd8-41c8d3634a29
date added to LUP
2017-03-21 13:19:18
date last changed
2017-09-18 11:33:29
@article{a420fc0b-0111-4f08-acd8-41c8d3634a29,
  abstract     = {Water loss is a crucial factor for vegetation in the semi-arid Sahel region of Africa. Global satellite-driven estimates of plant CO2 uptake (gross primary productivity, GPP) have been found to not accurately account for Sahelian conditions, particularly the impact of canopy water stress. Here, we identify the main biophysical limitations that induce canopy water stress in Sahelian vegetation and evaluate the relationships between field data and Earth observation-derived spectral products for up-scaling GPP. We find that plant-available water and vapor pressure deficit together control the GPP of Sahelian vegetation through their impact on the greening and browning phases. Our results show that a multiple linear regression (MLR) GPP model that combines the enhanced vegetation index, land surface temperature, and the short-wave infrared reflectance (Band 7, 2105–2155 nm) of the moderate-resolution imaging spectroradiometer satellite sensor was able to explain between 88% and 96% of the variability of eddy covariance flux tower GPP at three Sahelian sites (overall = 89%). The MLR GPP model presented here is potentially scalable at a relatively high spatial and temporal resolution. Given the scarcity of field data on CO2 fluxes in the Sahel, this scalability is important due to the low number of flux towers in the region.},
  articleno    = {294},
  author       = {Abdi, Abdulhakim and Boke-Olén, Niklas and Tenenbaum, David and Tagesson, Torbern and Cappelaere, Bernard and Ardö, Jonas},
  issn         = {2072-4292},
  keyword      = {Sahel,Drought,gross pri,Earth observation,Plant available water,Soil moisture,Vapor pressure deficit,Plant stress,Greening,Browning},
  language     = {eng},
  month        = {03},
  number       = {3},
  publisher    = {MDPI AG},
  series       = {Remote Sensing},
  title        = {Evaluating Water Controls on Vegetation Growth in the Semi-Arid Sahel Using Field and Earth Observation Data},
  url          = {http://dx.doi.org/10.3390/rs9030294},
  volume       = {9},
  year         = {2017},
}