TY - JOUR

T1 - A MODIS photochemical reflectance index (PRI) as an estimator of isoprene emissions in a temperate deciduous forest

AU - Filella, Iolanda

AU - Zhang, Chao

AU - Seco, Roger

AU - Potosnak, Mark

AU - Guenther, Alex

AU - Karl, Thomas

AU - Gamon, John

AU - Pallardy, Stephen

AU - Gu, Lianhong

AU - Kim, Saewung

AU - Balzarolo, Manuela

AU - Fernandez-Martinez, Marcos

AU - Penuelas, Josep

PY - 2018

Y1 - 2018

N2 - The quantification of isoprene and monoterpene emissions at the ecosystem level with available models and field measurements is not entirely satisfactory. Remote-sensing techniques can extend the spatial and temporal assessment of isoprenoid fluxes. Detecting the exchange of biogenic volatile organic compounds (BVOCs) using these techniques is, however, a very challenging goal. Recent evidence suggests that a simple remotely sensed index, the photochemical reflectance index (PRI), which is indicative of light-use efficiency, relative pigment levels and excess reducing power, is a good indirect estimator of foliar isoprenoid emissions. We tested the ability of PRI to assess isoprenoid fluxes in a temperate deciduous forest in central USA throughout the entire growing season and under moderate and extreme drought conditions. We compared PRI time series calculated with MODIS bands to isoprene emissions measured with eddy covariance. MODIS PRI was correlated with isoprene emissions for most of the season, until emissions peaked. MODIS PRI was also able to detect the timing of the annual peak of emissions, even when it was advanced in response to drought conditions. PRI is thus a promising index to estimate isoprene emissions when it is complemented by information on potential emission. It may also be used to further improve models of isoprene emission under drought and other stress conditions. Direct estimation of isoprene emission by PRI is, however, limited, because PRI estimates LUE, and the relationship between LUE and isoprene emissions can be modified by severe stress conditions.

AB - The quantification of isoprene and monoterpene emissions at the ecosystem level with available models and field measurements is not entirely satisfactory. Remote-sensing techniques can extend the spatial and temporal assessment of isoprenoid fluxes. Detecting the exchange of biogenic volatile organic compounds (BVOCs) using these techniques is, however, a very challenging goal. Recent evidence suggests that a simple remotely sensed index, the photochemical reflectance index (PRI), which is indicative of light-use efficiency, relative pigment levels and excess reducing power, is a good indirect estimator of foliar isoprenoid emissions. We tested the ability of PRI to assess isoprenoid fluxes in a temperate deciduous forest in central USA throughout the entire growing season and under moderate and extreme drought conditions. We compared PRI time series calculated with MODIS bands to isoprene emissions measured with eddy covariance. MODIS PRI was correlated with isoprene emissions for most of the season, until emissions peaked. MODIS PRI was also able to detect the timing of the annual peak of emissions, even when it was advanced in response to drought conditions. PRI is thus a promising index to estimate isoprene emissions when it is complemented by information on potential emission. It may also be used to further improve models of isoprene emission under drought and other stress conditions. Direct estimation of isoprene emission by PRI is, however, limited, because PRI estimates LUE, and the relationship between LUE and isoprene emissions can be modified by severe stress conditions.

KW - Drought

KW - GPP

KW - Isoprene

KW - LUE

KW - MEGAN

KW - MODIS

KW - Photorespiration

KW - PRI

KW - Reducing power

KW - Substrate availability

U2 - 10.3390/rs10040557

DO - 10.3390/rs10040557

M3 - Journal article

AN - SCOPUS:85045986337

VL - 10

JO - Remote Sensing

JF - Remote Sensing

SN - 2072-4292

IS - 4

M1 - 557

ER -