中文摘要：

Dansgaard于1964提出月尺度降水δ18O的的降水量效应（或称雨量效应），之后在古气候研究中被广泛应用于解释古季风强度的变化以及重建降水量。但在具有复合水源的中国季风区，这一应用遇到了困难。近年来，根据大量的观测数据，指出至少在中国季风区还存在另外一种同位素效应：环流效应。对于中国东部广大季风区来说，临近的太平洋提供近源水汽，而印度洋提供远源水汽。由于海洋和大气环流的变化，如热带太平洋海温梯度的变化，或西太平洋副热带高压的变化等，可导致从太平洋和印度洋向中国季风区输送的近远源水汽比率发生变化，从而导致了大气降水δ18O变化：无论降水量大或小，如果水汽来自太平洋，则降水δ18O的值偏高，如果水汽来自印度洋，则降水δ18O值偏低。本研究进一步分析了降水同位素季节尺度的环流效应，并引用SPR（江南春雨）这个气候学概念，成功地解释了2012年的降水量效应佯谬。降水同位素的环流效应概念不仅对同位素气象学和气候学有参考价值，也有助于我们理解作为古气候代用指标的占。℃的信号意义。

英文摘要：

The amount effect of δ18O in precipitation on a monthly scale proposed by Dansgaard in 1964 is widely applied to explain the variation of monsoon intensity or reconstruct precipitation amount over the paleoclimate research. However, it encounters difficulty in the monsoon regions of China （MRC）, which have composite water vapor sources. Recently, the authors point out that, according to observed data, there is another isotope effect in the MRC ： circulation effect. For most of the eastern parts of the MRC, the Pacific Ocean provides the adjacent source of water vapor, while the Indian Ocean provides the distant source of water vapor. The variability in the ocean and atmosphere circulations, such as the changes in the tropical Pacific SST gradient, or the West Pacific subtropical high, etc, could induce the changes in the ratio of water vapor from the Pacific Ocean and the Indian Ocean, which can then lead to the changes in the atmospheric precipitation δ18O（δ18Op） ： no matter how much of the precipitation amount, the δ18O value is relatively high if the water vapor from the Pacific Ocean, whereas the δ18Op value is relatively low if the water vapor from the Indian Ocean. In this paper, the authors report the analysis the circulation effect of table isotopes in precipitation on seasonal scale and cite the climatic concept of the SPR （ spring persistent rains） to successfully explain the paradox of the amount effect in 2012. Overall, the circulation effect of stable isotopes in precipitation is of significant not only for the isotope meteorology and climatology, but also for our understanding of the δ18O as paleoclimatic proxy. Key words persistent rains stable isotopes in precipitation, seasonal scale, amount effect, circulation effect, spring