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| Titel |
What controls deuterium excess in global precipitation? |
| VerfasserIn |
S. Pfahl, H. Sodemann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 2 ; Nr. 10, no. 2 (2014-04-22), S.771-781 |
| Datensatznummer |
250116952
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| Publikation (Nr.) |
 copernicus.org/cp-10-771-2014.pdf |
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| Zusammenfassung |
| The deuterium excess (d) of precipitation is widely used in the
reconstruction of past climatic changes from ice cores. However, its
most common interpretation as moisture source temperature cannot
directly be inferred from present-day water isotope
observations. Here, we use a new empirical relation between d and
near-surface relative humidity (RH) together with reanalysis data to
globally predict d of surface evaporation from the ocean. The very
good quantitative agreement of the predicted hemispherically averaged
seasonal cycle with observed d in precipitation indicates that
moisture source relative humidity, and not sea surface temperature, is
the main driver of d variability on seasonal timescales. Furthermore,
we review arguments for an interpretation of long-term palaeoclimatic d
changes in terms of moisture source temperature, and we conclude that
there remains no sufficient evidence that would justify to neglect the
influence of RH on such palaeoclimatic d variations. Hence, we suggest
that either the interpretation of d variations in palaeorecords should
be adapted to reflect climatic influences on RH during evaporation, in
particular atmospheric circulation changes, or new arguments for an
interpretation in terms of moisture source temperature will have to
be provided based on future research. |
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