Fig. 4 Regional atmospheric waterline in Wuhan (data from IAEA (1986–1998) and (Denget al. , 2016) (2011–2013)).
3.3 δ18O and δ2H isotope composition of soil water at the test site
Table 2 lists the general characteristics of the isotope composition of soil water. As can be observed, δ18O in soil water varies from −9.53‰ to −3.47‰, and δ2H ranges from −59.34‰ to −31.83‰ over a depth range of 0–30 cm from the surface during the test. The average values of δ18O and δ2H decreased gradually with depth, which indicates that the isotope fractionation caused by evaporation was more significant in the surface layer of the soil than that in the deeper layers.