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| Titel |
LGM permafrost distribution: how well can the latest PMIP multi-model ensembles perform reconstruction? |
| VerfasserIn |
K. Saito, T. Sueyoshi, S. Marchenko, V. Romanovsky, B. Otto-Bliesner, J. Walsh, N. Bigelow, A. Hendricks, K. Yoshikawa |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2013-08-01), S.1697-1714 |
| Datensatznummer |
250018101
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| Publikation (Nr.) |
 copernicus.org/cp-9-1697-2013.pdf |
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| Zusammenfassung |
| Here, global-scale frozen ground distribution from the Last Glacial Maximum
(LGM) has been reconstructed using multi-model ensembles of global climate
models, and then compared with evidence-based knowledge and earlier
numerical results. Modeled soil temperatures, taken from Paleoclimate
Modelling Intercomparison Project phase III (PMIP3) simulations, were used
to diagnose the subsurface thermal regime and determine underlying frozen
ground types for the present day (pre-industrial; 0 kya) and the LGM (21 kya).
This direct method was then compared to an earlier indirect method, which
categorizes underlying frozen ground type from surface air temperature,
applying to both the PMIP2 (phase II) and PMIP3 products. Both direct and
indirect diagnoses for 0 kya showed strong agreement with the present-day
observation-based map. The soil temperature ensemble showed a higher
diversity around the border between permafrost and seasonally frozen ground
among the models, partly due to varying subsurface processes,
implementation, and settings. The area of continuous permafrost estimated by
the PMIP3 multi-model analysis through the direct (indirect) method was 26.0
(17.7) million km2 for LGM, in contrast to 15.1 (11.2) million km2
for the pre-industrial control, whereas seasonally frozen ground decreased
from 34.5 (26.6) million km2 to 18.1 (16.0) million km2. These
changes in area resulted mainly from a cooler climate at LGM, but from other
factors as well, such as the presence of huge land ice sheets and the
consequent expansion of total land area due to sea-level change. LGM
permafrost boundaries modeled by the PMIP3 ensemble – improved over those of
the PMIP2 due to higher spatial resolutions and improved climatology – also
compared better to previous knowledge derived from geomorphological and
geocryological evidence. Combinatorial applications of coupled climate
models and detailed stand-alone physical-ecological models for the
cold-region terrestrial, paleo-, and modern climates will advance our
understanding of the functionality and variability of the frozen ground
subsystem in the global eco-climate system. |
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