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| DOI：10.13522/j.cnki.ggps.2019286 |
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| The Relationship between δ18O in Precipitation in Eastern China and the ENSO |
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DUAN Lianqiang, LIU Fenghua, SU Yongjun, KONG Shuqin
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1.Cangzhou Water Conservancy Survey and Design Institute, Cangzhou 061000, China;2.Hebei University of Water Resources and Electric Engineering, Cangzhou 061001, China
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| Abstract: |
| 【Background】Stable isotopes in precipitation are influenced by atmospheric moisture dynamics, precipitation pattern, temperature, humidity and altitude. The El Ni?o-Southern Oscillation (ENSO) is a Global Coupled Ocean-Atmosphere event that plays an important role in inter-annual climate change. The variation in atmospheric moisture and ENSO has a prominent impact on hydrological cycle and characteristics of isotopes in precipitation in monsoon season in east Asia.【Objective】This paper aims to analyze the response of stable isotopes in precipitation in east Asia to variation in atmospheric moisture and the ENSO in order to improve our understanding of water cycle in this region.【Method】We divided the region to three sub-regions: northeast, north and south. Based on the stable isotopes in precipitation and meteorological data measured from 60 weather stations across the region, a nonlinear regression model was derived to link latitude and δ18O in the precipitation using the BW model to calculate spatial distribution of the stable oxygen isotopes. We also analyzed the temporal change in δ18O and the meteorological data at each station. The relationship between the ENSO and the stable isotopes was analyzed using the OLR method.【Result】The concentration of δ18O decreased gradually from the southeast to the northwest and was affected by terrain at significant level; it was higher in winter and lower in summer. In general, the ENSO had a significant impact on temperature, and thus, in La Nina year, the δ18O was related to the temperature strongly in the northeast and south while weakly in the north. The OLR value of the moisture showed that we can rank its impact in the order of El Nino year > normal year > La Nina year, consistent with the change in δ18O. The change in ITCZ was strongly related to the stable isotope in the precipitation, but the impact varied with local climate and their correlation was not significant in the northeast.【Conclusion】Atmospheric moisture and air convection have a better correlation with the stable isotope in precipitation in east China. The results presented in this paper could improve our understanding of the impact of ENSO on stable isotopes which have a wide application. |
| Key words: stable isotopes in precipitation; ENSO event; OLR field; ITCZ; eastern China |
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