Stable Isotope Compositions for Meteoric Water from Chengdu and Their Implication of Climate

Isotopic compositions for meteoric water from Chengdu during 1986～1998 are analyzed. δD and δ18O values of precipitation in summer are much lighter than those of precipitation in winter which is characteristic of monsoon climate. Meteoric water line for Chengdu is: δD = 1.42+7.530δ18O. The intercept and the slope are low compared with global and China meteoric water line which reflects the unbalance condition of precipitation. Excess deuterium is relatively small which shows that unbalance condition of precipitation in evaporation and agglomeration was faint. This is characteristic of oceanic climate. δ18O for precipitation is in positive correlation with rainfall, temperature and water press, however, rainfall is the most important factor that works on δ18O for precipitation.