 |
| Titel |
Late-glacial to late-Holocene shifts in global precipitation δ18O |
| VerfasserIn |
S. Jasechko, A. Lechler, F. S. R. Pausata, P. J. Fawcett, T. Gleeson, D. I. Cendón, J. Galewsky, A. N. LeGrande, C. Risi, Z. D. Sharp, J. M. Welker, M. Werner, K. Yoshimura |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 10 ; Nr. 11, no. 10 (2015-10-14), S.1375-1393 |
| Datensatznummer |
250117437
|
| Publikation (Nr.) |
 copernicus.org/cp-11-1375-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Reconstructions of Quaternary climate are often based on the isotopic
content of paleo-precipitation preserved in proxy records. While many
paleo-precipitation isotope records are available, few studies have
synthesized these dispersed records to explore spatial patterns of
late-glacial precipitation δ18O. Here we present a synthesis
of 86 globally distributed groundwater (n = 59), cave calcite (n = 15) and
ice core (n = 12) isotope records spanning the late-glacial (defined as
~ 50 000 to ~ 20 000 years ago) to the
late-Holocene (within the past ~ 5000 years). We show that
precipitation δ18O changes from the late-glacial to the
late-Holocene range from −7.1 ‰ (δ18Olate-Holocene > δ18Olate-glacial) to +1.7 ‰ (δ18Olate-glacial > δ18Olate-Holocene), with the majority (77 %) of records
having lower late-glacial δ18O than late-Holocene δ18O values. High-magnitude, negative precipitation δ18O
shifts are common at high latitudes, high altitudes and continental
interiors (δ18Olate-Holocene > δ18Olate-glacial by more than 3 ‰).
Conversely, low-magnitude, positive precipitation δ18O shifts
are concentrated along tropical and subtropical coasts (δ18Olate-glacial > δ18Olate-Holocene by less than 2 ‰).
Broad, global patterns of late-glacial to late-Holocene precipitation
δ18O shifts suggest that stronger-than-modern isotopic
distillation of air masses prevailed during the late-glacial, likely
impacted by larger global temperature differences between the tropics and
the poles. Further, to test how well general circulation models reproduce
global precipitation δ18O shifts, we compiled simulated
precipitation δ18O shifts from five isotope-enabled general
circulation models simulated under recent and last glacial maximum climate
states. Climate simulations generally show better inter-model and
model-measurement agreement in temperate regions than in the tropics,
highlighting a need for further research to better understand how
inter-model spread in convective rainout, seawater δ18O and
glacial topography parameterizations impact simulated precipitation δ18O. Future research on paleo-precipitation δ18O records
can use the global maps of measured and simulated late-glacial
precipitation isotope compositions to target and prioritize field sites. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|