Isotopic composition of water in precipitation in a region or place.

Stable isotopes of water molecules in hydrology, the water cycle and Craig's global meteoric water line (GMWL) relating δ(18)O and δ(2)H are well established with a slope of around 8 and an intercept of around 10. However, in many situations the slope is less than 8 and the intercept is smaller or even negative. These observations need to be understood and a method is suggested to correlate with the global meteoric water line (GMWL). How to find the isotopic composition of water at a particular place is also suggested.