Dataset Information

Variations in atmospheric CO2 growth rates coupled with tropical temperature.

ABSTRACT: Previous studies have highlighted the occurrence and intensity of El Niño-Southern Oscillation as important drivers of the interannual variability of the atmospheric CO2 growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r(2) ? 0.50) between interannual variations of the CO2 growth rate and tropical land-surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to a 3.5 ± 0.6 Petagrams of carbon per year (PgC/y) CO2 growth-rate anomaly on average. Analysis of simulation results from Dynamic Global Vegetation Models suggests that this temperature-CO2 coupling is contributed mainly by the additive responses of heterotrophic respiration (Rh) and net primary production (NPP) to temperature variations in tropical ecosystems. However, we find a weaker and less consistent (r(2) ? 0.25) interannual coupling between CO2 growth rate and tropical land precipitation than diagnosed from the Dynamic Global Vegetation Models, likely resulting from the subtractive responses of tropical Rh and NPP to precipitation anomalies that partly offset each other in the net ecosystem exchange (i.e., net ecosystem exchange ? Rh - NPP). Variations in other climate variables (e.g., large-scale cloudiness) and natural disturbances (e.g., volcanic eruptions) may induce transient reductions in the temperature-CO2 coupling, but the relationship is robust during the past 50 y and shows full recovery within a few years after any such major variability event. Therefore, it provides an important diagnostic tool for improved understanding of the contemporary and future global carbon cycle.

SUBMITTER: Wang W

PROVIDER: S-EPMC3740858 | biostudies-other | 2013 Aug

REPOSITORIES: biostudies-other

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Variations in atmospheric CO2 growth rates coupled with tropical temperature.

Wang Weile W Ciais Philippe P Nemani Ramakrishna R RR Canadell Josep G JG Piao Shilong S Sitch Stephen S White Michael A MA Hashimoto Hirofumi H Milesi Cristina C Myneni Ranga B RB

Proceedings of the National Academy of Sciences of the United States of America 20130724 32

Previous studies have highlighted the occurrence and intensity of El Niño-Southern Oscillation as important drivers of the interannual variability of the atmospheric CO2 growth rate, but the underlying biogeophysical mechanisms governing such connections remain unclear. Here we show a strong and persistent coupling (r(2) ≈ 0.50) between interannual variations of the CO2 growth rate and tropical land-surface air temperature during 1959 to 2011, with a 1 °C tropical temperature anomaly leading to ...[more]

PMID: 23884654

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Variations in atmospheric CO2 growth rates coupled with tropical temperature.

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Variations in atmospheric CO2 growth rates coupled with tropical temperature.

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