Abstract: Because of the temperature and precipitation impact, there is an intensive seasonal varying of precipitation δ¹⁸O under the temperate continental and monsoon climate in the most of China. In northern part of China, predominant by the fluctuant air temperature, precipitation δ¹⁸O has a strong temperature effect, and even on the monthly scale there is a significant positive correlation with precipitation amount. However, recently, several studies showed that there was also a significant or insignificant precipitation amount effect on the precipitation event scale especially for the rainy summer season. In this study, precipitation δ¹⁸O downloaded from GNIP with monthly meteorological data was reanalyzed. The result showed that when the variation of air temperature and precipitation frequency were sorted out to remove their influence, there was a significant negative correlation between precipitation intensity on the monthly scale all year round (P=0.012). The significant temperature and precipitation intensive effect yearly were (0.45±0.03)‰\5℃^-1 (T=17.38, P<0.001) and (-0.28±0.12)‰·mm^-1 (T=-2.29, P=0.023), respectively. In the four seasons, temperature and precipitation intensive effect all coexisted, and they shifted and dominated the fluctuation of precipitation δ¹⁸O in different seasons, respectively. In spring and autumn, it was predominated by the significant temperature effect because of the strong fluctuation in air temperature. In hot summer, it was predominated by the significant precipitation intensity effect of (-0.49±0.17)‰·mm^-1 (T=-2.93, P=0.006). Although in cold winter, the temperature and precipitation intensity effect were both insignificant, the latter also was larger than the former.

Key words: seasonal fluctuation, temperature effect, precipitation intensity effect, δ¹⁸O