Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series
Depiction of phenological cycles in tropical forests is critical for an understanding of seasonal patterns in carbon and water fluxes as well as the responses of vegetation to climate variations. However, the detection of clear spatially explicit phenological patterns across Amazonia has proven diff...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2013-01-01
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| Series: | Environmental Research Letters |
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| Online Access: | https://doi.org/10.1088/1748-9326/8/2/024011 |
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| author | Fabrício B Silva Yosio E Shimabukuro Luiz E O C Aragão Liana O Anderson Gabriel Pereira Franciele Cardozo Egídio Arai |
| author_facet | Fabrício B Silva Yosio E Shimabukuro Luiz E O C Aragão Liana O Anderson Gabriel Pereira Franciele Cardozo Egídio Arai |
| author_sort | Fabrício B Silva |
| collection | DOAJ |
| description | Depiction of phenological cycles in tropical forests is critical for an understanding of seasonal patterns in carbon and water fluxes as well as the responses of vegetation to climate variations. However, the detection of clear spatially explicit phenological patterns across Amazonia has proven difficult using data from the Moderate Resolution Imaging Spectroradiometer (MODIS). In this work, we propose an alternative approach based on a 26-year time-series of the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR) to identify regions with homogeneous phenological cycles in Amazonia. Specifically, we aim to use a pattern recognition technique, based on temporal signal processing concepts, to map Amazonian phenoregions and to compare the identified patterns with field-derived information. Our automated method recognized 26 phenoregions with unique intra-annual seasonality. This result highlights the fact that known vegetation types in Amazonia are not only structurally different but also phenologically distinct. Flushing of new leaves observed in the field is, in most cases, associated to a continuous increase in NDVI. The peak in leaf production is normally observed from the beginning to the middle of the wet season in 66% of the field sites analyzed. The phenoregion map presented in this work gives a new perspective on the dynamics of Amazonian canopies. It is clear that the phenology across Amazonia is more variable than previously detected using remote sensing data. An understanding of the implications of this spatial heterogeneity on the seasonality of Amazonian forest processes is a crucial step towards accurately quantifying the role of tropical forests within global biogeochemical cycles. |
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| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-12T16:04:40Z |
| publishDate | 2013-01-01 |
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| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-7f7c7aa45e824c0cb5962203ccfe1a502023-08-09T14:26:16ZengIOP PublishingEnvironmental Research Letters1748-93262013-01-018202401110.1088/1748-9326/8/2/024011Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-seriesFabrício B Silva0Yosio E Shimabukuro1Luiz E O C Aragão2Liana O Anderson3Gabriel Pereira4Franciele Cardozo5Egídio Arai6National Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, BrazilNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, BrazilNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, Brazil; College of Life and Environmental Sciences, University of Exeter , Exeter EX4 4RJ, UKNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, Brazil; Environmental Change Institute, University of Oxford , South Parks Road, Oxford, OX1 3QY, UKNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, BrazilNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, BrazilNational Institute for Space Research , Avenida dos Astronautas 1758, São José dos Campos-SP, BrazilDepiction of phenological cycles in tropical forests is critical for an understanding of seasonal patterns in carbon and water fluxes as well as the responses of vegetation to climate variations. However, the detection of clear spatially explicit phenological patterns across Amazonia has proven difficult using data from the Moderate Resolution Imaging Spectroradiometer (MODIS). In this work, we propose an alternative approach based on a 26-year time-series of the normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR) to identify regions with homogeneous phenological cycles in Amazonia. Specifically, we aim to use a pattern recognition technique, based on temporal signal processing concepts, to map Amazonian phenoregions and to compare the identified patterns with field-derived information. Our automated method recognized 26 phenoregions with unique intra-annual seasonality. This result highlights the fact that known vegetation types in Amazonia are not only structurally different but also phenologically distinct. Flushing of new leaves observed in the field is, in most cases, associated to a continuous increase in NDVI. The peak in leaf production is normally observed from the beginning to the middle of the wet season in 66% of the field sites analyzed. The phenoregion map presented in this work gives a new perspective on the dynamics of Amazonian canopies. It is clear that the phenology across Amazonia is more variable than previously detected using remote sensing data. An understanding of the implications of this spatial heterogeneity on the seasonality of Amazonian forest processes is a crucial step towards accurately quantifying the role of tropical forests within global biogeochemical cycles.https://doi.org/10.1088/1748-9326/8/2/024011tropical forestvegetation indexAmazoniaphenologyleaf flushingremote sensing |
| spellingShingle | Fabrício B Silva Yosio E Shimabukuro Luiz E O C Aragão Liana O Anderson Gabriel Pereira Franciele Cardozo Egídio Arai Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series Environmental Research Letters tropical forest vegetation index Amazonia phenology leaf flushing remote sensing |
| title | Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series |
| title_full | Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series |
| title_fullStr | Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series |
| title_full_unstemmed | Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series |
| title_short | Large-scale heterogeneity of Amazonian phenology revealed from 26-year long AVHRR/NDVI time-series |
| title_sort | large scale heterogeneity of amazonian phenology revealed from 26 year long avhrr ndvi time series |
| topic | tropical forest vegetation index Amazonia phenology leaf flushing remote sensing |
| url | https://doi.org/10.1088/1748-9326/8/2/024011 |
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