1. Equilibrium fractionation
h=1
vapor
liquid
[18O/16O]
equilibrium
a18Owater-vapor =
[18O/16O]water/[18O/16O]vapor > 1
h: relative humidity

2. Rayleigh distillation5 10 15 20 25 30
0.2
0.4
0.6
0.8 1
f (fraction of liquid water remaining)
d18O (‰)
h=1
vapor
liquid
[18O/16O]
evaporation
equilibrium
fraction of water remaining
relative humidity
h :

3. Kinetic fractionation
Similar for 18O and 2H
Depends on relative humidity and roughness of the ocean
h<1
vapor
liquid
[18O/16O]
non-equilibrium

4. first rain
ocean water
second rain
evaporation
third rain
evaporation of surface water
kinetic frac.
first vapor, equilibrium

5. Evaporation slopes:

7. d18O, d2H influenced by: local temperature amount of precipitation
altitude
moisture transport pattern
distance from coast (continental effect)
evaporation
Mixing with ocean water
………..

8. Rainout as function of temperature

9. Temperature effect
Dansgaard, 1964

10. Amount effect
IAEA, 1982

11. Global Network Isotopes in Precipitation (GNIP)
IAEA (2001).  GNIP Maps and Animations, International Atomic Energy Agency, Vienna. 

12. IAEA (2001).  GNIP Maps and Animations, International Atomic Energy Agency, Vienna.