2000 Fiscal Year Final Research Report Summary
Studies on Continental Hydrological Cycle Using Water Isotope Global Circulation Model
| Project/Area Number |
11640426
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NUMAGUTI Atusi Hokkaido Univ., Grad.School of Env.Sci., Asso.Prof., 大学院・地球環境科学研究科, 助教授 (30237797)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Ayako Univ.Tokyo, Cent.Clim.System Res., Inst., 気候システム研究センター, 助手 (30272537)
TSUJIMURA Maki Univ.Tsukuba, Inst.Geoscience, Lec., 地球科学系, 講師 (10273301)
SUGIMOTO Atsuko Kyoto Univ., Center for Ecolog.Res., Asso.Prof., 生態学研究センター, 助教授 (50235892)
YAMANAKA Yasuhiro Hokkaido Univ., Grad.School of Env.Sci., Asso.Prof., 大学院・地球環境科学研究科, 助教授 (40242177)
YAMAZAKI Koji Hokkaido Univ., Grad.School of Env.Sci., Prof., 大学院・地球環境科学研究科, 教授 (70270791)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Hydrological Cycle / Stable Isotope / General Circulation Model / Material Transport / Transport Scheme / Precipitation / Continental Evaporation / Eurasian Continent |
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| Research Abstract |
A Water Isotope Global Circulation Model (WI-GCM) is developed based on CCSR/NIES Atmospheric General Circulation Model (AGCM) including global circulation of oxygen and hydrogen isotope with revised treatment of mixed-phase cloud, evaporation of precipitating drop, and evaporation from ocean. The simulated isotope ratio is found to be consistent with the results of GNIP observations. Further, thenumerical scheme of transport of water in the atmosphere is replaced by newly developed grid-base advection scheme with flux-form semi-Lagrangean treatment. It is found that this replacement of transport scheme improves not only the hydrological cycle of polar region but also the simulation of isotope ratio.
Comparing the model results with observed isotope ratio in precipitation in Tibet, Siberia, and other regions, some utility of isotope for the study of mechanisms and variability of the hydrological cycle. In Tibet, an importance of water vapor which is originated from evaporation of precipitating drop from convective cloud is suggested. In Siberia, interannual variation of recycling process between land and atmosphere is suggested by observed interannual variation of isotope. In Antarctica, an interannualvariation of isotope ratio related with the interannual change of transport route connected with ENSO variation is identified.
Comparing the observed water isotope ratio in the soil and plant with model results it is suggested that the improved treatment of soil water and fractionation by evaporation from land surface is important future study.
It is concluded that we have succeeded in building a useful tool for the quantitative studies on hydrological cycle by using water isotope.
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