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Drivers of δ 2 H variations in an idealized extratropical cyclone
Author(s) -
Dütsch Marina,
Pfahl Stephan,
Wernli Heini
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl068600
Subject(s) - extratropical cyclone , advection , fractionation , atmospheric sciences , cold front , precipitation , water vapor , environmental science , cyclone (programming language) , warm front , isotope , isotope fractionation , meteorology , climatology , geology , chemistry , thermodynamics , physics , nuclear physics , organic chemistry , field programmable gate array , computer science , computer hardware
Numerical model simulations of stable water isotopes help to improve our understanding of the complex processes driving isotopic variability in atmospheric moisture. We use the isotope‐enabled Consortium for Small‐Scale Modelling (COSMO) model to study the governing mechanisms of δ 2 H variations in an idealized extratropical cyclone. A set of experiments with differing initial conditions of δ 2 H in vapor and partly deactivated isotopic fractionation allows us to quantify the relative roles of cloud fractionation and vertical and horizontal advection for the simulated δ 2 H signals associated with the cyclone and fronts. Horizontal transport determines the large‐scale pattern of δ 2 H in both vapor and precipitation, while fractionation and vertical transport are more important on a smaller scale, near the fronts. During the passage of the cold front fractionation leads to a V‐shaped trend of δ 2 H in precipitation and vapor, which is, for vapor, superimposed on a gradual decrease caused by the arrival of colder air masses.