2022 Fiscal Year Research-status Report
Implementation of tritium in the General Circulation Model MIROC to investigate the dynamics of the hydrological cycle
| Project/Area Number |
22K20379
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2022-08-31 – 2024-03-31
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| Keywords | tritium / MIROC / solar activity / water cycle / stratosphere / water isotopes / GCM |
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| Outline of Annual Research Achievements |
General circulation models (GCMs) are used to study the Earth's climate system and project its future changes. However, the representation of the water cycle in these models remains a challenge. So, this project provides the incorporation of the tracer tritium into the MIROC Earth system model to improve the modeling of the hydrological cycle. Tritium is a very valuable tracer of the water cycle because it is a strong marker of the involved reservoirs such as the stratosphere, the troposphere and the oceans.
This tracer has been successfully implemented in the isotopic version of the atmospheric GCM MIROC5, MIROC5-iso. Next, I used for the first time the natural tritium production modulated by solar activity to run a simulation over the period 1979-2018 to study the impact of solar activity on the water cycle and climate.
Anthropogenic tritium production by nuclear bombs in the 1960s is coded and will be tested very soon.
This work will be presented in July 2023 at the Hydrology Symposium of the IAEA in Vienna, Austria.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Tritium has been implemented successfully in MIROC5-iso, and a run with the tritium production depending on solar activity changes has been performed. This is the first time that such simulation is made. The results are very promising and will be presented at the IAEA hydrology symposium in July 2023. A first paper is also planned. The coding of the bomb-tritium part is now finished and will be tested very soon with different reanalyses (ERA5 and JRA55) for the nudging.
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| Strategy for Future Research Activity |
The results of the solar activity run are very promising and will be presented at the IAEA hydrology symposium in July 2023 as a keynote lecture. A first paper is also planned.
The coding of the bomb-tritium part is now finished and will be tested very soon. Once the simulations hopefully performed for the period 1952-2018, we should be able to investigate the effects of the choice on reanalyses for nudging on the tritium simulation, and so on the transport of water water in the atmosphere. A second paper on this aspect is then also planned.
The development of the coupled atmosphere-ocean isotope-enabled model MIROC6-iso is going well. Once this development phase finished, I will be able to adapt my tritium code for this model to get the first coupled simulation with tritium tracer.
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| Causes of Carryover |
The grant has been received in October 2022 while the major conferences are from April 2023. Moreover, it was necessary to first code the tritium in the model to get publishable or presentable results. The remaining amount of FY2022 will be used in FY2023 for travel expenses at international conferences or for the payment of publication fee.
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