15
IRUS TotalDownloads
Altmetric
Isoprene emissions track the seasonal cycle of canopy temperature, not primary production: evidence from remote sensing
File | Description | Size | Format | |
---|---|---|---|---|
bg-11-3437-2014.pdf | Published version | 807.55 kB | Adobe PDF | View/Open |
Title: | Isoprene emissions track the seasonal cycle of canopy temperature, not primary production: evidence from remote sensing |
Authors: | Foster, PN Prentice, IC Morfopoulos, C Siddall, M Van Weele, M |
Item Type: | Journal Article |
Abstract: | Isoprene is important in atmospheric chemistry, but its seasonal emission pattern – especially in the tropics, where most isoprene is emitted – is incompletely understood. We set out to discover generalized relationships applicable across many biomes between large-scale isoprene emission and a series of potential predictor variables, including both observed and model-estimated variables related to gross primary production (GPP) and canopy temperature. We used remotely sensed atmospheric concentrations of formaldehyde, an intermediate oxidation product of isoprene, as a proxy for isoprene emission in 22 regions selected to span high to low latitudes, to sample major biomes, and to minimize interference from pyrogenic sources of volatile organic compounds that could interfere with the isoprene signal. Formaldehyde concentrations showed the highest average seasonal correlations with remotely sensed (r = 0.85) and model-estimated (r = 0.80) canopy temperatures. Both variables predicted formaldehyde concentrations better than air temperature (r= 0.56) and a "reference" isoprene model that combines GPP and an exponential function of temperature (r = 0.49), and far better than either remotely sensed green vegetation cover, fPAR (r = 0.25) or model-estimated GPP (r = 0.14). Gross primary production in tropical regions was anti-correlated with formaldehyde concentration (r = −0.30), which peaks during the dry season. Our results were most reliable in the tropics, where formaldehyde observational errors were the least. The tropics are of particular interest because they are the greatest source of isoprene emission as well as the region where previous modelling attempts have been least successful. We conjecture that positive correlations of isoprene emission with GPP and air temperature (as found in temperate forests) may arise simply because both covary with canopy temperature, peaking during the relatively short growing season. The lack of a general correlation between GPP and formaldehyde concentration in the seasonal cycle is consistent with experimental evidence that isoprene emission rates are largely decoupled from photosynthetic rates, and with the likely adaptive significance of isoprene emission in protecting leaves against heat damage and oxidative stress. |
Issue Date: | 1-Jul-2014 |
Date of Acceptance: | 16-May-2014 |
URI: | http://hdl.handle.net/10044/1/69646 |
DOI: | https://dx.doi.org/10.5194/bg-11-3437-2014 |
ISSN: | 1726-4170 |
Publisher: | Copernicus Publications |
Start Page: | 3437 |
End Page: | 3451 |
Journal / Book Title: | Biogeosciences |
Volume: | 11 |
Issue: | 13 |
Copyright Statement: | © 2014 Author(s). This work is distributed under the Creative Commons Attribution 3.0 License (https://creativecommons.org/licenses/by/3.0/). |
Keywords: | Science & Technology Life Sciences & Biomedicine Physical Sciences Ecology Geosciences, Multidisciplinary Environmental Sciences & Ecology Geology TERRESTRIAL ECOSYSTEMS MONOTERPENE EMISSION MODEL FORMALDEHYDE CLIMATE THERMOTOLERANCE PHOTOSYNTHESIS VARIABILITY VEGETATION MEMBRANES 04 Earth Sciences 05 Environmental Sciences 06 Biological Sciences Meteorology & Atmospheric Sciences |
Publication Status: | Published |
Open Access location: | https://www.biogeosciences.net/11/3437/2014/bg-11-3437-2014.pdf |
Online Publication Date: | 2014-07-01 |
Appears in Collections: | Department of Life Sciences Grantham Institute for Climate Change |