論文

査読有り
2020年5月13日

Development of the MIROC-ES2L Earth system model and the evaluation of biogeochemical processes and feedbacks

Geoscientific Model Development
  • Tomohiro Hajima
  • ,
  • Michio Watanabe
  • ,
  • Akitomo Yamamoto
  • ,
  • Hiroaki Tatebe
  • ,
  • Maki A. Noguchi
  • ,
  • Manabu Abe
  • ,
  • Rumi Ohgaito
  • ,
  • Akinori Ito
  • ,
  • Dai Yamazaki
  • ,
  • Hideki Okajima
  • ,
  • Akihiko Ito
  • ,
  • Kumiko Takata
  • ,
  • Koji Ogochi
  • ,
  • Shingo Watanabe
  • ,
  • Michio Kawamiya

13
5
開始ページ
2197
終了ページ
2244
記述言語
掲載種別
研究論文(学術雑誌)
DOI
10.5194/gmd-13-2197-2020
出版者・発行元
Copernicus GmbH

Abstract. This article describes the new Earth system model (ESM), the Model for
Interdisciplinary Research on Climate, Earth System version 2 for Long-term
simulations (MIROC-ES2L), using a state-of-the-art climate model as the
physical core. This model embeds a terrestrial biogeochemical component with
explicit carbon–nitrogen interaction to account for soil nutrient control
on plant growth and the land carbon sink. The model's ocean biogeochemical
component is largely updated to simulate the biogeochemical cycles of carbon,
nitrogen, phosphorus, iron, and oxygen such that oceanic primary
productivity can be controlled by multiple nutrient limitations. The ocean
nitrogen cycle is coupled with the land component via river discharge
processes, and external inputs of iron from pyrogenic and lithogenic sources
are considered. Comparison of a historical simulation with observation
studies showed that the model could reproduce the transient global climate
change and carbon cycle as well as the observed large-scale spatial patterns
of the land carbon cycle and upper-ocean biogeochemistry. The model
demonstrated historical human perturbation of the nitrogen cycle through
land use and agriculture and simulated the resultant impact on the
terrestrial carbon cycle. Sensitivity analyses under preindustrial
conditions revealed that the simulated ocean biogeochemistry could be
altered regionally (and substantially) by nutrient input from the atmosphere
and rivers. Based on an idealized experiment in which CO2 was
prescribed to increase at a rate of 1 % yr−1, the transient climate
response (TCR) is estimated to be 1.5 K, i.e., approximately 70 % of that from
our previous ESM used in the Coupled Model Intercomparison Project Phase 5
(CMIP5). The cumulative airborne fraction (AF) is also reduced by 15 %
because of the intensified land carbon sink, which results in an airborne
fraction close to the multimodel mean of the CMIP5 ESMs. The transient
climate response to cumulative carbon emissions (TCRE) is 1.3 K EgC−1,
i.e., slightly smaller than the average of the CMIP5 ESMs, which suggests
that “optimistic” future climate projections will be made by the model.
This model and the simulation results contribute to CMIP6. The MIROC-ES2L
could further improve our understanding of climate–biogeochemical
interaction mechanisms, projections of future environmental changes, and
exploration of our future options regarding sustainable development by
evolving the processes of climate, biogeochemistry, and human activities in
a holistic and interactive manner.

リンク情報
DOI
https://doi.org/10.5194/gmd-13-2197-2020
URL
https://www.geosci-model-dev.net/13/2197/2020/gmd-13-2197-2020.pdf

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