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| Titel |
East Asian Monsoon controls on the inter-annual variability in precipitation isotope ratio in Japan |
| VerfasserIn |
N. Kurita, Y. Fujiyoshi, T. Nakayama, Y. Matsumi, H. Kitagawa |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 2 ; Nr. 11, no. 2 (2015-02-25), S.339-353 |
| Datensatznummer |
250117172
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| Publikation (Nr.) |
 copernicus.org/cp-11-339-2015.pdf |
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| Zusammenfassung |
To elucidate the mechanism for how the East Asian Monsoon (EAM)
variability have influenced the isotope proxy records in Japan, we
explore the primary driver of variations of precipitation isotopes
at multiple temporal scales (event, seasonal and inter-annual scales).
Using a new 1-year record of the isotopic composition of
event-based precipitation and continuous near-surface
water vapor at Nagoya in central Japan, we identify the key atmospheric
processes controlling the storm-to-storm isotopic variations through
an analysis of air mass sources and rainout history during the transport
of moisture to the site, and then apply the identified processes to
explain the inter-annual isotopic variability related to the EAM variability
in the historical 17-year long Tokyo station record in
the Global Network of Isotopes in Precipitation (GNIP).
In the summer, southerly flows transport moisture with higher
isotopic values from subtropical marine regions and bring warm rainfall
enriched with heavy isotopes.
The weak monsoon summer corresponds to enriched isotopic
values in precipitation, reflecting higher contribution of warm rainfall to the
total summer precipitation.
In the strong monsoon summer, the sustaining Baiu rainband
along the southern coast of Japan prevents moisture transport
across Japan, so that the contribution of warm rainfall is reduced.
In the winter, storm tracks are the dominant driver of storm-to-storm
isotopic variation and relatively low isotopic values occur when
a cold frontal rainband associated with extratropical cyclones passes
off to the south of the Japan coast.
The weak monsoon winter is characterized by lower isotopes in precipitation, due
to the distribution of the cyclone tracks away from the southern coast of Japan.
In contrast, the northward shift of the cyclone tracks and stronger
development of cyclones during the strong monsoon winters
decrease the contribution of cold frontal precipitation, resulting in higher
isotopic values in winter precipitation.
Therefore, year-to-year isotopic variability in summer and winter Japanese
precipitation correlates significantly with changes in the East Asian summer and winter
monsoon intensity (R=-0.47 for summer, R=0.42 for winter), and thus we conclude
that the isotope proxy records in Japan should reflect past changes in the East Asian Monsoon.
Since our study identifies the climate drivers controlling isotopic variations in summer and winter
precipitation, we highlight the retrieval of a record with seasonal resolution from paleoarchives
as an important priority. |
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