The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests
Satellite remote sensing has the potential to contribute to plant phenology monitoring at spatial and temporal scales relevant for regional and global scale studies. Historically, temporal composites of satellite data, ranging from 8 days to 16 days, have been used as a starting point for satellite-...
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Online Access: | https://digitalcommons.usu.edu/aspen_bib/7386 http://www.sciencedirect.com/science/article/pii/S0034425711000587 |
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ftutahsudc:oai:digitalcommons.usu.edu:aspen_bib-8397 |
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Utah State University: DigitalCommons@USU |
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topic |
Phenology Leaf unfolding AVHRR NDVI Aspen Agriculture Ecology and Evolutionary Biology Forest Sciences Genetics and Genomics Plant Sciences |
spellingShingle |
Phenology Leaf unfolding AVHRR NDVI Aspen Agriculture Ecology and Evolutionary Biology Forest Sciences Genetics and Genomics Plant Sciences Kross, Angela Fernandes, RIchard Seaquist, Jonathan Beaubien, Elisabeth The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
topic_facet |
Phenology Leaf unfolding AVHRR NDVI Aspen Agriculture Ecology and Evolutionary Biology Forest Sciences Genetics and Genomics Plant Sciences |
description |
Satellite remote sensing has the potential to contribute to plant phenology monitoring at spatial and temporal scales relevant for regional and global scale studies. Historically, temporal composites of satellite data, ranging from 8 days to 16 days, have been used as a starting point for satellite-derived phenology data sets. In this study we assess how the temporal resolution of such composites affects the estimation of the start of season (SOS) by: 1) calibrating a relationship between satellite derived SOS with in situ leaf unfolding (LU) of trembling aspen (Populus tremuloides) across Canada and 2) quantifying the sensitivity of calibrated satellite SOS estimates and trends, over Canadian broadleaf forests, to the temporal resolution of NDVI data. SOS estimates and trends derived from daily NDVI data were compared to SOS estimates and trends derived from multiday NDVI composites that retain the exact date of the maximum NDVI value or that assume the midpoint of the multiday interval as the observation date. In situobservations of LU dates were acquired from the PlantWatch Canada network. A new Canadian database of cloud and snow screened daily 1-km resolution National Oceanic and Atmospheric Administration advanced very high resolution radiometer surface reflectance images was used as input satellite data. The mean absolute errors of SOS dates with respect to in situ LU dates ranged between 13 and 40 days. SOS estimates from NDVI composites that retain the exact date of the maximum NDVI value had smaller errors (~ 13 to 20 days). The sensitivity analysis reinforced these findings: SOS estimates from NDVI composites that use the exact date had smaller absolute deviations from the LU date (0 to − 5 days) than the SOS estimates from NDVI composites that use the midpoint (− 2 to − 27 days). The SOS trends between 1985 and 2007 were not sensitive to the temporal resolution or compositing methods. However, SOS trends at individual ecozones showed significant differences with the SOS trends from daily NDVI data (Taiga plains and the Pacific maritime zones). Overall, our results suggest that satellite based estimates of vegetation green-up dates should preferably use sub-sampled NDVI composites that include the exact observation date of the maximum NDVI to minimize errors in both, SOS estimates and SOS trend analyses. For trend analyses alone, any of the compositing methods could be used, preferably with composite intervals of less than 28 days. This is an important finding, as it suggests that existing long-term 10-day or 15-day NDVI composites could be used for SOS trend analyses over broadleaf forests in Canada or similar areas. Future studies will take advantage of the growing in situ phenology networks to improve the validation of satellite derived green-up dates. |
format |
Text |
author |
Kross, Angela Fernandes, RIchard Seaquist, Jonathan Beaubien, Elisabeth |
author_facet |
Kross, Angela Fernandes, RIchard Seaquist, Jonathan Beaubien, Elisabeth |
author_sort |
Kross, Angela |
title |
The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
title_short |
The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
title_full |
The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
title_fullStr |
The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
title_full_unstemmed |
The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests |
title_sort |
effect of the temporal resolution of ndvi data on season onset dates and trends across canadian broadleaf forests |
publisher |
Hosted by Utah State University Libraries |
publishDate |
2011 |
url |
https://digitalcommons.usu.edu/aspen_bib/7386 http://www.sciencedirect.com/science/article/pii/S0034425711000587 |
geographic |
Canada Pacific |
geographic_facet |
Canada Pacific |
genre |
taiga Taiga plains |
genre_facet |
taiga Taiga plains |
op_source |
Aspen Bibliography |
op_relation |
https://digitalcommons.usu.edu/aspen_bib/7386 http://www.sciencedirect.com/science/article/pii/S0034425711000587 |
op_rights |
Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact the Institutional Repository Librarian at digitalcommons@usu.edu. |
op_rightsnorm |
PDM |
_version_ |
1766214815635734528 |
spelling |
ftutahsudc:oai:digitalcommons.usu.edu:aspen_bib-8397 2023-05-15T18:31:08+02:00 The effect of the temporal resolution of NDVI data on season onset dates and trends across Canadian broadleaf forests Kross, Angela Fernandes, RIchard Seaquist, Jonathan Beaubien, Elisabeth 2011-01-01T08:00:00Z https://digitalcommons.usu.edu/aspen_bib/7386 http://www.sciencedirect.com/science/article/pii/S0034425711000587 unknown Hosted by Utah State University Libraries https://digitalcommons.usu.edu/aspen_bib/7386 http://www.sciencedirect.com/science/article/pii/S0034425711000587 Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact the Institutional Repository Librarian at digitalcommons@usu.edu. PDM Aspen Bibliography Phenology Leaf unfolding AVHRR NDVI Aspen Agriculture Ecology and Evolutionary Biology Forest Sciences Genetics and Genomics Plant Sciences text 2011 ftutahsudc 2022-03-07T21:27:28Z Satellite remote sensing has the potential to contribute to plant phenology monitoring at spatial and temporal scales relevant for regional and global scale studies. Historically, temporal composites of satellite data, ranging from 8 days to 16 days, have been used as a starting point for satellite-derived phenology data sets. In this study we assess how the temporal resolution of such composites affects the estimation of the start of season (SOS) by: 1) calibrating a relationship between satellite derived SOS with in situ leaf unfolding (LU) of trembling aspen (Populus tremuloides) across Canada and 2) quantifying the sensitivity of calibrated satellite SOS estimates and trends, over Canadian broadleaf forests, to the temporal resolution of NDVI data. SOS estimates and trends derived from daily NDVI data were compared to SOS estimates and trends derived from multiday NDVI composites that retain the exact date of the maximum NDVI value or that assume the midpoint of the multiday interval as the observation date. In situobservations of LU dates were acquired from the PlantWatch Canada network. A new Canadian database of cloud and snow screened daily 1-km resolution National Oceanic and Atmospheric Administration advanced very high resolution radiometer surface reflectance images was used as input satellite data. The mean absolute errors of SOS dates with respect to in situ LU dates ranged between 13 and 40 days. SOS estimates from NDVI composites that retain the exact date of the maximum NDVI value had smaller errors (~ 13 to 20 days). The sensitivity analysis reinforced these findings: SOS estimates from NDVI composites that use the exact date had smaller absolute deviations from the LU date (0 to − 5 days) than the SOS estimates from NDVI composites that use the midpoint (− 2 to − 27 days). The SOS trends between 1985 and 2007 were not sensitive to the temporal resolution or compositing methods. However, SOS trends at individual ecozones showed significant differences with the SOS trends from daily NDVI data (Taiga plains and the Pacific maritime zones). Overall, our results suggest that satellite based estimates of vegetation green-up dates should preferably use sub-sampled NDVI composites that include the exact observation date of the maximum NDVI to minimize errors in both, SOS estimates and SOS trend analyses. For trend analyses alone, any of the compositing methods could be used, preferably with composite intervals of less than 28 days. This is an important finding, as it suggests that existing long-term 10-day or 15-day NDVI composites could be used for SOS trend analyses over broadleaf forests in Canada or similar areas. Future studies will take advantage of the growing in situ phenology networks to improve the validation of satellite derived green-up dates. Text taiga Taiga plains Utah State University: DigitalCommons@USU Canada Pacific |