 |
| Titel |
Early and mid-Holocene climate in the tropical Pacific: seasonal cycle and interannual variability induced by insolation changes |
| VerfasserIn |
Y. Luan, P. Braconnot, Y. Yu, W. Zheng, O. Marti |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 3 ; Nr. 8, no. 3 (2012-06-29), S.1093-1108 |
| Datensatznummer |
250005599
|
| Publikation (Nr.) |
 copernicus.org/cp-8-1093-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| Using a coupled atmosphere-ocean model we analyze the responses of the mean
climate and interannual variations in the tropical Pacific to the changes in
insolation during the early and mid-Holocene, with experiments in which only
the variations of Earth's orbital configuration are considered. We first
discuss common features of the Early and mid-Holocene climates compared to
the pre-industrial conditions. In particular, an equatorial annual mean
cooling that has a "U" shape across the tropical Pacific is simulated,
whereas the ocean heat content is enhanced in the western tropical Pacific
and decreased in the east. Similarly, the seasonality is enhanced in the
west and reduced in the east. We show that the seasonality of the insolation
forcing, the cloud radiative forcing and ocean dynamics all contribute to
increasing these east–west contrasts. ENSO variability is reduced in the
early Holocene and increases towards present-day conditions. Obliquity alone
does not affect ENSO characteristics in the model. The reduction of ENSO
magnitude results from the relationship between changes in seasonality,
which involves wave propagation along the thermocline, and the timing of the
development of ENSO anomalies. All these effects are larger in the Early
Holocene compared to the mid-Holocene. Despite a one-month difference in the
insolation forcing and corresponding response of SST, winds and thermocline
depth between these two periods, the timing and changes in the east–west
temperature and heat content gradients are similar. We suggest that it
explains why the timing of development of ENSO is quite similar between
these two climates and does not reflect the differences in the seasonal timing. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|