 |
| Titel |
A 70-yr record of oxygen-18 variability in an ice core from the Tanggula Mountains, central Tibetan Plateau |
| VerfasserIn |
D. R. Joswiak, T. Yao, G. Wu, B. Xu, W. Zheng |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 6, no. 2 ; Nr. 6, no. 2 (2010-04-08), S.219-227 |
| Datensatznummer |
250003445
|
| Publikation (Nr.) |
 copernicus.org/cp-6-219-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| A 33 m ice core was retrieved from the Tanggula Mts, central Tibetan Plateau
at 5743 m a.s.l. in August 2005. Annual average δ18O values
were determined for the upper 17 m depth (14.6 m w.eq.), representing the
time series since the mid-1930s. Data are compared to previous results of an
ice core from Mt. Geladaindong, 100 km to the northwest, for the period
1935–2003. During the time 1935–1960, δ18O values differed by
2–3‰ between the two ice cores, with generally lower ratios preserved in the
Tanggula 2005 core. Differences in interannual variability and overall
average ratios between the two study locations highlight the spatially
variable climate controls on ice core isotope ratios within the boundary of
monsoon- and westerly-impacted regions of the central Tibetan Plateau.
Average annual net accumulation was 261 mm w.eq. for the period 1935–2004.
The overall average δ18O value was −13.2‰ and exhibited a
statistically significant increase from the 1935–1969 average (−13.7‰) to
the 1970–2004 average (−12.6‰). Despite the observed increase in isotope
ratios, isotopic temperature dependence was not evident, based on comparison
with long-term data from meteorological stations to the north and southwest
of the study location. Lack of correlation between average δ18O
values and temperature is likely due to monsoon influence, which results in
relatively greater isotopic depletion of moisture during the warm season.
Evidence of monsoon impacts on precipitation in the central Tibetan Plateau
has been previously documented, and statistically significant negative
correlation (r=−0.37, p<0.01) between the annual average ice core
δ18O values and North India monsoon rainfall was observed for the period
1935–2004. Although the δ18O data agree well with the monsoon
rainfall amount, no significant correlation was observed between the core
accumulation and the monsoon rainfall amount. Previous model and
observational results suggest monsoon impact on δ18O in
precipitation may extend beyond the immediate extent of heavy monsoon
rainfall, reaching the central Tibetan Plateau. These results provide
evidence that the δ18O variability at this study location may
be sensitive to southern monsoon intensity. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|