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Title: A Functional Response Metric for the Temperature Sensitivity of Tropical Ecosystems

Abstract

Earth system models (ESMs) simulate a large spread in carbon cycle feedbacks to climate change, particularly in their prediction of cumulative changes in terrestrial carbon storage. Evaluating the performance of ESMs against observations and assessing the likelihood of long-term climate predictions are crucial for model development. Here, we assessed the use of atmospheric CO 2 growth rate variations to evaluate the sensitivity of tropical ecosystem carbon fluxes to interannual temperature variations. We found that the temperature sensitivity of the observed CO 2 growth rate depended on the time scales over which atmospheric CO 2 observations were averaged. The temperature sensitivity of the CO 2 growth rate during Northern Hemisphere winter is most directly related to the tropical carbon flux sensitivity since winter variations in Northern Hemisphere carbon fluxes are relatively small. This metric can be used to test the fidelity of interactions between the physical climate system and terrestrial ecosystems within ESMs, which is especially important since the short-term relationship between ecosystem fluxes and temperature stress may be related to the long-term feedbacks between ecosystems and climate. If the interannual temperature sensitivity is used to constrain long-term temperature responses, the inferred sensitivity may be biased by 20%, unless the seasonalitymore » of the relationship between the observed CO 2 growth rate and tropical fluxes is taken into account. Lastly, these results suggest that atmospheric data can be used directly to evaluate regional land fluxes from ESMs, but underscore that the interaction between the time scales for land surface processes and those for atmospheric processes must be considered.« less

Authors:
 [1];  [1]; ORCiD logo [2]
  1. Univ. of Michigan, Ann Arbor, MI (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1436930
Alternate Identifier(s):
OSTI ID: 1434230
Grant/Contract Number:
AC05-00OR22725; AC05-000OR2275
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Earth Interactions
Additional Journal Information:
Journal Volume: 22; Journal Issue: 7; Journal ID: ISSN 1087-3562
Publisher:
American Meteorological Association
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Tropics; Carbon dioxide; Climate models; Model evaluation/performance; Atmosphere-land interaction; Ecosystem effects

Citation Formats

Keppel-Aleks, Gretchen, Basile, Samantha J., and Hoffman, Forrest M. A Functional Response Metric for the Temperature Sensitivity of Tropical Ecosystems. United States: N. p., 2018. Web. doi:10.1175/EI-D-17-0017.1.
Keppel-Aleks, Gretchen, Basile, Samantha J., & Hoffman, Forrest M. A Functional Response Metric for the Temperature Sensitivity of Tropical Ecosystems. United States. doi:10.1175/EI-D-17-0017.1.
Keppel-Aleks, Gretchen, Basile, Samantha J., and Hoffman, Forrest M. Mon . "A Functional Response Metric for the Temperature Sensitivity of Tropical Ecosystems". United States. doi:10.1175/EI-D-17-0017.1.
@article{osti_1436930,
title = {A Functional Response Metric for the Temperature Sensitivity of Tropical Ecosystems},
author = {Keppel-Aleks, Gretchen and Basile, Samantha J. and Hoffman, Forrest M.},
abstractNote = {Earth system models (ESMs) simulate a large spread in carbon cycle feedbacks to climate change, particularly in their prediction of cumulative changes in terrestrial carbon storage. Evaluating the performance of ESMs against observations and assessing the likelihood of long-term climate predictions are crucial for model development. Here, we assessed the use of atmospheric CO2 growth rate variations to evaluate the sensitivity of tropical ecosystem carbon fluxes to interannual temperature variations. We found that the temperature sensitivity of the observed CO2 growth rate depended on the time scales over which atmospheric CO2 observations were averaged. The temperature sensitivity of the CO2 growth rate during Northern Hemisphere winter is most directly related to the tropical carbon flux sensitivity since winter variations in Northern Hemisphere carbon fluxes are relatively small. This metric can be used to test the fidelity of interactions between the physical climate system and terrestrial ecosystems within ESMs, which is especially important since the short-term relationship between ecosystem fluxes and temperature stress may be related to the long-term feedbacks between ecosystems and climate. If the interannual temperature sensitivity is used to constrain long-term temperature responses, the inferred sensitivity may be biased by 20%, unless the seasonality of the relationship between the observed CO2 growth rate and tropical fluxes is taken into account. Lastly, these results suggest that atmospheric data can be used directly to evaluate regional land fluxes from ESMs, but underscore that the interaction between the time scales for land surface processes and those for atmospheric processes must be considered.},
doi = {10.1175/EI-D-17-0017.1},
journal = {Earth Interactions},
number = 7,
volume = 22,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2018},
month = {Mon Apr 23 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on April 23, 2019
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