|
Titel |
Influence of orbital forcing and solar activity on water isotopes in precipitation during the mid- and late Holocene |
VerfasserIn |
S. Dietrich, M. Werner, T. Spangehl, G. Lohmann |
Medientyp |
Artikel
|
Sprache |
Englisch
|
ISSN |
1814-9324
|
Digitales Dokument |
URL |
Erschienen |
In: Climate of the Past ; 9, no. 1 ; Nr. 9, no. 1 (2013-01-08), S.13-26 |
Datensatznummer |
250017422
|
Publikation (Nr.) |
copernicus.org/cp-9-13-2013.pdf |
|
|
|
Zusammenfassung |
In this study we investigate the impact of mid- and late Holocene orbital
forcing and solar activity on variations of the oxygen isotopic composition
in precipitation. The investigation is motivated by a recently published
speleothem δ18O record from the well-monitored Bunker Cave in
Germany. The record reveals some high variability on multi-centennial to
millennial scales that does not linearly correspond to orbital forcing. Our
model study is based on a set of novel climate simulations performed with the
atmosphere general circulation model ECHAM5-wiso enhanced by explicit water
isotope diagnostics. From the performed model experiments, we derive the
following major results: (1) the response of both orbital and solar forcing
lead to changes in surface temperatures and δ18O in precipitation
with similar magnitudes during the mid- and late Holocene. (2) Past
δ18O anomalies correspond to changing temperatures in the orbital
driven simulations. This does not hold true if an additional solar forcing is
added. (3) Two orbital driven mid-Holocene experiments, simulating the mean
climate state approximately 5000 and 6000 yr ago, yield very similar
results. However, if an identical additional solar activity-induced forcing
is added, the simulated changes of surface temperatures as well as
δ18O between both periods differ. We conclude from our simulation
results that non-linear effects and feedbacks of the orbital and solar
activity forcing substantially alter the δ18O in precipitation
pattern and its relation to temperature change. |
|
|
Teil von |
|
|
|
|
|
|