Open AccessInfluence of atmospheric circulation patterns on the oxygen isotope ratio of tree rings in the Alpine region
Author(s) -
Saurer Matthias,
Kress Anne,
Leuenberger Markus,
Rinne Katja T.,
Treydte Kerstin S.,
Siegwolf Rolf T. W.
Publication year - 2012
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jd016861
Subject(s) - precipitation , environmental science , dendrochronology , climatology , atmospheric circulation , atmospheric sciences , δ18o , relative humidity , humidity , isotopes of oxygen , stable isotope ratio , geology , meteorology , geography , physics , paleontology , geochemistry , quantum mechanics
The oxygen isotope ratio of precipitation and tree rings is a complex function of climate variables and atmospheric dynamics, which often makes the interpretation of δ 18 O for palaeoclimate research challenging. Here we analyzed monthly precipitation δ 18 O series for 1973–2004 and annually resolved tree ring δ 18 O chronologies for 1945–2004 for three sites in Switzerland: one north of the Alps, one at high‐elevation within the Alps, and one south of the Alps. The goal of the study was to improve the understanding of the tree ring archive by a systematic analysis of nonlocal parameters related to atmospheric circulation, in particular, geopotential height field anomalies and the frequency of synoptic weather situations, in addition to the usual local climate parameters like temperature, sunshine duration, and relative humidity. We observed that on average high‐pressure situations during summer were associated with relatively high δ 18 O and low‐pressure situations were associated with relatively low δ 18 O, for both the isotope ratio in precipitation and tree rings. However, correlations to the frequency of weather types were not higher than simple correlations to local temperature. Accordingly, we constructed a combined index from temperature and air pressure that proved to be a good predictor of δ 18 O in precipitation and used this as the source water term in a tree ring isotope fractionation model. This enabled us to use the model beyond the period where isotope values for precipitation are available, opening new perspectives in the interpretation of long tree ring δ 18 O chronologies.