Correlation of the seasonal isotopic amplitude of precipitation with annual evaporation and altitude in alpine regions.

The time series of stable water isotope composition relative to IAEA-GNIP meteorological stations located in alpine zones are analyzed in order to study how the amplitude of the seasonal isotopic composition of precipitation ( A δ ) varies along a vertical transect. A clear relationship between A δ and local evaporation is obtained, with slopes of − 0.87 ‰/100 mm/yr and − 7.3 ‰/100 mm/yr for A δ 18 O and A δ 2 H , respectively. When all sampling points of the vertical transect receive the same moisture sources, then a linear relationship between A δ and elevation is obtained, with vertical gradients of 0.16 ‰/100 mm/yr and 1.46 ‰/100 mm/yr for A δ 18 O and A δ 2 H , respectively. [ABSTRACT FROM AUTHOR]