A tropical speleothem record of glacial inception, the South American Summer Monsoon from 125 to 115 ka
Relatively few marine or terrestrial paleoclimate studies have focused on glacial inception, the transition from an interglacial to a glacial climate state. As a result, neither the timing and structure of glacial inception nor the spatial pattern of glacial inception in different parts of the world...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
|
| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/11/931/2015/cp-11-931-2015.pdf |
| Summary: | Relatively few marine or terrestrial paleoclimate studies have focused on
glacial inception, the transition from an interglacial to a glacial climate
state. As a result, neither the timing and structure of glacial inception nor the spatial pattern of glacial inception in different parts of
the world is well known. Here we present results of a study of a speleothem from the
Peruvian Andes that records changes in the intensity of South American Summer
Monsoon (SASM) rainfall over the period from 125 to 115 ka. The results show
that late in the last interglacial period, at 123 ka, SASM rainfall
decreased, perhaps in response to a decrease in temperature and ice cover in
the high northern latitudes and associated changes in atmospheric
circulation. Then at 120.8 ka, a rapid increase in SASM rainfall marks the
end of the last interglacial. After a more gradual increase between 120 and
117 ka, a second abrupt increase occurs at 117 ka. This pattern of change
is mirrored to a remarkable degree by changes in the East Asian Monsoon. It
is interpreted to reflect both a long-term gradual response of the monsoons
to orbitally driven insolation changes and to rapid changes in Northern
Hemisphere ice volume and temperature. Both monsoon systems are close to
their full glacial conditions by 117 ka, before any significant decrease in
atmospheric CO<sub>2</sub>. |
|---|---|
| ISSN: | 1814-9324 1814-9332 |