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Abstract Warming climate in the Arctic is leading to an increase in isoprene emission from ecosystems. We assessed the influence of temperature on isoprene emission from Arctic willows with laboratory and field measurements. Our findings indicate that the hourly temperature response curve ofSalixspp., the dominant isoprene emitting shrub in the Arctic, aligns with that of temperate plants. In contrast, the isoprene capacity of willows exhibited a more substantial than expected response to the mean ambient temperature of the previous day, which is much stronger than the daily temperature response predicted by the current version of the Model of Emissions of Gases and Aerosols from Nature (MEGAN). With a modified algorithm from this study, MEGAN predicts 66% higher isoprene emissions for Arctic willows during an Arctic heatwave. However, despite these findings, we are still unable to fully explain the high temperature sensitivity of isoprene emissions from high latitude ecosystems.
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Intra- and interannual changes in isoprene emission from central Amazonia
Abstract. Isoprene emissions are a key component in biosphere–atmosphere interactions, and the most significant global source is the Amazonrainforest. However, intra- and interannual variations in biological and environmental factors that regulate isoprene emission from Amazonia arenot well understood and, thereby, are poorly represented in models. Here, with datasets covering several years of measurements at the Amazon Tall TowerObservatory (ATTO) in central Amazonia, Brazil, we (1) quantified canopy profiles of isoprene mixing ratios across seasons of normal and anomalousyears and related them to the main drivers of isoprene emission – solar radiation, temperature, and leaf phenology; (2) evaluated the effect ofleaf age on the magnitude of the isoprene emission factor (Es) from different tree species and scaled up to canopy with intra- andinterannual leaf age distribution derived by a phenocam; and (3) adapted the leaf age algorithm from the Model of Emissions of Gasesand Aerosols from Nature (MEGAN) with observed changes in Esacross leaf ages. Our results showed that the variability in isoprene mixing ratios was higher between seasons (max during the dry-to-wettransition seasons) than between years, with values from the extreme 2015 El Niño year not significantly higher than in normal years. Inaddition, model runs considering in situ observations of canopy Es and the modification on the leaf age algorithm with leaf-levelobservations of Es presented considerable improvements in the simulated isoprene flux. This shows that MEGAN estimates of isopreneemission can be improved when biological processes are mechanistically incorporated into the model.
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- Award ID(s):
- 1754163
- PAR ID:
- 10562649
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- EGU Copernicus
- Date Published:
- Journal Name:
- Atmospheric Chemistry and Physics
- Volume:
- 23
- Issue:
- 14
- ISSN:
- 1680-7324
- Page Range / eLocation ID:
- 8149 to 8168
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.5194/acp-23-8149-2023
