In hydrology and related studies, a cline (from Ancient Greek κλίνειν (klínein) 'to lean') is a comparatively thin, typically horizontal layer within a fluid, in which a property of the fluid varies greatly over a relatively short vertical distance.
Such clines and the respectively varying properties include:
- Chemocline - chemistry[1]
- Halocline - salinity[2]
- Lysocline - dissolution of calcite[3]
- Pycnocline - density[4]
- Thermocline - temperature[5]