TY - JOUR
T1 - Multiple site tower flux and remote sensing comparisons of tropical forest dynamics in Monsoon Asia
AU - Huete, A. R.
AU - Restrepo-Coupe, N.
AU - Ratana, P.
AU - Didan, K.
AU - Saleska, S. R.
AU - Ichii, K.
AU - Panuthai, S.
AU - Gamo, M.
N1 - Funding Information:
We greatly thank the Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for the availability of MODIS subsetted land products, Collection 5, for all three flux tower sites [ http://www.daac.ornl.gov/MODIS/modis.html ]. This study was supported by NASA MODIS contract NNG04HZ20C.
PY - 2008/5/15
Y1 - 2008/5/15
N2 - The spatial and temporal dynamics of tropical forest functioning are poorly understood, partly attributed to a weak seasonality and high tree species diversity at the landscape scale. Recent neotropical rainforest studies with local tower flux measurements have revealed strong seasonal carbon fluxes that follow the availability of sunlight in intact forests, while in areas of forest disturbance, carbon fluxes more closely tracked seasonal water availability. These studies also showed a strong seasonal correspondence of satellite measures of greenness, using the Enhanced Vegetation Index (EVI) with ecosystem carbon fluxes in both intact and disturbed forests, which may enable larger scale extension of tower flux measurements. In this study, we investigated the seasonal patterns and relationships of local site tower flux measures of gross primary productivity (Pg) with independent Moderate Resolution Imaging Spectroradiometer (MODIS) satellite greenness measures across three Monsoon Asia tropical forest types, encompassing drought-deciduous, dry evergreen, and humid evergreen secondary tropical forests. In contrast to neotropical forests, the tropical forests of Monsoon Asia are more extensively degraded and heterogeneous due to intense land use pressures, and therefore, may exhibit unique seasonal patterns of ecosystem fluxes that are more likely water-limited and drought-susceptible. Our results show significant phenologic variability and response to moisture and light controls across the three tropical forest sites and at the regional scale. The drier tropical forests were primarily water-limited, while the wet evergreen secondary forest showed a slight positive trend with light availability. Satellite EVI greenness observations were generally synchronized and linearly related with seasonal and inter-annual tower flux Pg measurements at the multiple sites and provided better opportunities for tower extension of carbon fluxes than other satellite products, such as the MODIS Pg product. Satellite EVI-derived Pg images revealed strong seasonal variations in photosynthetic activity throughout the Monsoon Asia tropical region.
AB - The spatial and temporal dynamics of tropical forest functioning are poorly understood, partly attributed to a weak seasonality and high tree species diversity at the landscape scale. Recent neotropical rainforest studies with local tower flux measurements have revealed strong seasonal carbon fluxes that follow the availability of sunlight in intact forests, while in areas of forest disturbance, carbon fluxes more closely tracked seasonal water availability. These studies also showed a strong seasonal correspondence of satellite measures of greenness, using the Enhanced Vegetation Index (EVI) with ecosystem carbon fluxes in both intact and disturbed forests, which may enable larger scale extension of tower flux measurements. In this study, we investigated the seasonal patterns and relationships of local site tower flux measures of gross primary productivity (Pg) with independent Moderate Resolution Imaging Spectroradiometer (MODIS) satellite greenness measures across three Monsoon Asia tropical forest types, encompassing drought-deciduous, dry evergreen, and humid evergreen secondary tropical forests. In contrast to neotropical forests, the tropical forests of Monsoon Asia are more extensively degraded and heterogeneous due to intense land use pressures, and therefore, may exhibit unique seasonal patterns of ecosystem fluxes that are more likely water-limited and drought-susceptible. Our results show significant phenologic variability and response to moisture and light controls across the three tropical forest sites and at the regional scale. The drier tropical forests were primarily water-limited, while the wet evergreen secondary forest showed a slight positive trend with light availability. Satellite EVI greenness observations were generally synchronized and linearly related with seasonal and inter-annual tower flux Pg measurements at the multiple sites and provided better opportunities for tower extension of carbon fluxes than other satellite products, such as the MODIS Pg product. Satellite EVI-derived Pg images revealed strong seasonal variations in photosynthetic activity throughout the Monsoon Asia tropical region.
KW - AsiaFlux
KW - MODIS E
KW - Phenology
KW - Remote sensing
KW - Tropical forests
UR - http://www.scopus.com/inward/record.url?scp=43049103751&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=43049103751&partnerID=8YFLogxK
U2 - 10.1016/j.agrformet.2008.01.012
DO - 10.1016/j.agrformet.2008.01.012
M3 - Article
AN - SCOPUS:43049103751
SN - 0168-1923
VL - 148
SP - 748
EP - 760
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
IS - 5
ER -