Global meteoric water line

The GMWL was first developed in 1961 by Harmon Craig, and has subsequently been widely used to track water masses in environmental geochemistry and hydrogeology.

The relationship of δ18O and δ2H in meteoric water is caused by mass dependent fractionation of oxygen and hydrogen isotopes between evaporation from ocean seawater and condensation from vapor.

The fractionation processes can be influenced by a number of factors including: temperature, latitude, continentality, and most importantly, humidity.

[7] The δ18O of ancient meteoric water, preserved in ice cores, can also be collected and applied to reconstruct paleoclimate.

[14] However, for certain purposes such as the evaluation of the shifts from the line of the geothermal waters, it would be more appropriate to calculate the so-called "prediction interval" or "error wings" related to LMWL.

Global meteoric water line. Data are global annual average 18 O and 2 H values from precipitation monitored at IAEA network stations distributed globally (n=420). [ 1 ]
Local meteoric water line of Changsha, China, 1990. Data are monthly 18 O and 2 H values from precipitation monitored at the local station (n=12). [ 5 ]