EGU2020-6491
https://doi.org/10.5194/egusphere-egu2020-6491
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Two aspects of decadal ENSO variability modulating the long-term global carbon cycle

So-won Park1, Jin-Soo Kim2,3, Jong-Seong Kug1, Malte F. Stuecker4,5,6, In-Won Kim5,6, and Mathew Williams2,3
So-won Park et al.
  • 1Pohang University of Science and Technology (POSTECH), Division of Environmental Science and Engineering, Korea, Republic of (sowon@postech.ac.kr)
  • 2School of GeoSciences, University of Edinburgh, Edinburgh, United Kingdom (jinddu@gmail.com, Mat.Williams@ed.ac.uk)
  • 3National Centre for Earth Observation, University of Edinburgh, Edinburgh, United Kingdom (jinddu@gmail.com, Mat.Williams@ed.ac.uk)
  • 4Department of Oceanography and International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaiʻi at Mānoa, Honolulu, HI, USA (malte.stuecker@gmail.com)
  • 5Center for Climate Physics, Institute for Basic Science (IBS), Busan, South Korea (malte.stuecker@gmail.com, iwkimi@pusan.ac.kr)
  • 6Pusan National University, Busan, South Korea (malte.stuecker@gmail.com, iwkimi@pusan.ac.kr)

El Niño-Southern Oscillation (ENSO) is the primary cause of interannual variations in the global carbon cycle because ENSO-driven extensive teleconnection over continents affects the terrestrial ecosystem process. ENSO is an interannual phenomenon, but it also has decadal variability. The ENSO-like SST pattern and ENSO characteristic, e.g. ENSO amplitude, change on decadal timescales. However, the influence of decadal ENSO variability on global carbon cycle has not yet been fully examined. Here we examined the impacts of decadal ENSO variability on decadal variation of terrestrial carbon flux by analyzing fully coupled pre-industrial control simulation of the Community Earth System Model 1 large ensemble (CESM1-LE). Considerable decadal variability of atmosphere-to-land carbon flux exists and this terrestiral carbon flux is mainly modulated by the tropical biosphere on decadal timescales as well as on interannual timescales. We found that there are two different pathways, which can explain about 36% of the decadal variations in terrestrial carbon flux. First, long-term climate change over tropics induced by decadal tropical Pacific SST variability regulates the terrestrial productivity and hence atmospheric CO2 on decadal time scale. Second, decadal changes in asymmetric terrestrial ecosystem’s response to ENSO events, resulted from decadal modulation of ENSO amplitude, generate decadal variability of terrestrial carbon flux.

Key words: Global Carbon Cycle, El Niño-Southern Oscillation (ENSO), Pacific Decadal Variability, ENSO asymmetry, Decadal NBP variability

How to cite: Park, S., Kim, J.-S., Kug, J.-S., Stuecker, M. F., Kim, I.-W., and Williams, M.: Two aspects of decadal ENSO variability modulating the long-term global carbon cycle, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6491, https://doi.org/10.5194/egusphere-egu2020-6491, 2020

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