3.3 Meteoric Water Line (MWL)
The meteoric water lines (MWL) of atmospheric precipitation in Xiamen city from 2018 to 2019, including the total meteoric water line, typhoon precipitation meteoric water line, normal precipitation meteoric water line and seasonal meteoric water lines, were established based on the sample data collected during the study period (Fig. 5). The slope of the total meteoric water line (δD = 7.93δ18O + 1.77) in the study area is similar to that of the Global Meteoric Water Line (GMWL, δD = 8δ18O + 10) (Dansgaard, 1964) and the Eastern China Meteoric Water Line (CMWL, δD = 7.9δ18O + 8.2) (Zheng et al., 1983), but the intercept distance is significantly smaller than that of the two. The intercept of the typhoon-related precipitation meteoric water line is also smaller than that of the GMWL and CMWL. In addition, the intercept and slope of the seasonal meteoric water lines are quite different. The slope was the highest in summer monsoon period with 8.75, followed by seasonal shift period of 7.38, and the winter monsoon period was the lowest with 6.30 and has the only negative intercept of -3.58.
[Insert Figure 5]