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High‐resolution diatom δ 18 O records, from the last 150 years, reflecting changes in amount of winter precipitation in two sub‐Arctic high‐altitude lakes in the Swedish Scandes
Author(s) -
Jonsson Christina E.,
Rosqvist Gunhild C.,
Leng Melanie J.,
Bigler Christian,
Bergman Jonas,
Tillman Päivi Kaislahti,
Sloane Hilary J.
Publication year - 2010
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.1372
Subject(s) - diatom , precipitation , altitude (triangle) , effects of high altitude on humans , snow , snowmelt , arctic , environmental science , oceanography , climatology , physical geography , geology , geography , meteorology , geomorphology , geometry , mathematics
Waters from high‐altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high‐altitude lakes have lake water isotopic compositions ( δ 18 O lake ) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water δ 18 O. Here we compare two high‐resolution δ 18 O diatom records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900–1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in δ 18 O diatom as decreasing trends. Lowest δ 18 O diatom values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the δ 18 O diatom signal in these sub‐Arctic high‐altitude lakes with short residence times has been changes in amount of winter precipitation and that δ 18 O diatom derived from high‐altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy. Copyright © 2010 John Wiley & Sons, Ltd.