scholarly journals Features of the zonal mean circulation in the Southern Hemisphere during the Last Glacial Maximum

2007 ◽  
Vol 112 (D2) ◽  
Author(s):  
Frank Drost ◽  
James Renwick ◽  
B. Bhaskaran ◽  
Hilary Oliver ◽  
James McGregor
Keyword(s):  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Mean Circulation ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Breakdown of the Linear Relationship between the Southern Hemisphere Hadley Cell Edge and Jet Latitude Changes in the Last Glacial Maximum

2020 ◽  
Vol 33 (13) ◽  
pp. 5713-5725
Author(s):  
Seo-Yeon Kim ◽  
Seok-Woo Son
Keyword(s):  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Cold Climate ◽  
Hadley Cell ◽  
Last Glacial ◽  
Intercomparison Project ◽  
Mean Circulation ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractA poleward displacement of the Hadley cell (HC) edge and the eddy-driven jet latitude has been observed in the Southern Hemisphere (SH) during the last few decades. This change is further projected to continue in the future, indicating coherent tropical and extratropical zonal-mean circulation changes from the present climate to a warm climate. Here we show that such a systematic change in the zonal-mean circulation change does not hold in a cold climate. By examining the Last Glacial Maximum (LGM), preindustrial (PI), and extended concentration pathway 4.5 (ECP4.5) scenarios archived for phase 3 of the Paleoclimate Modeling Intercomparison Project (PMIP3) and phase 5 of the Coupled Model Intercomparison Project (CMIP5), it is shown that while the annual-mean SH HC edge systematically shifts poleward from the LGM scenario to the PI scenario and then to the ECP4.5 scenario the annual-mean SH eddy-driven jet latitude does not. All models show a poleward jet shift from the PI scenario to the ECP4.5 scenario, but over one-half of the models exhibit no trend or even an equatorward jet shift from the LGM scenario to the PI scenario. This decoupling between the HC edge and jet latitude changes is most pronounced in SH winter when the Antarctic surface cooling in the LGM scenario is comparable to or larger than the tropical upper-tropospheric cooling. This result indicates that polar amplification could play a crucial role in driving the decoupling of the tropical and midlatitude zonal-mean circulation in the SH in a cold climate.

Southern Hemisphere westerly wind changes during the Last Glacial Maximum: paleo-data synthesis

2013 ◽  
Vol 68 ◽  
pp. 76-95 ◽  
Author(s):  
K.E. Kohfeld ◽  
R.M. Graham ◽  
A.M. de Boer ◽  
L.C. Sime ◽  
E.W. Wolff ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Westerly Wind ◽  
Data Synthesis ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison

2013 ◽  
Vol 64 ◽  
pp. 104-120 ◽  
Author(s):  
Louise C. Sime ◽  
Karen E. Kohfeld ◽  
Corinne Le Quéré ◽  
Eric W. Wolff ◽  
Agatha M. de Boer ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Westerly Wind ◽  
Model Data ◽  
Last Glacial ◽  
Data Comparison ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Influence of boundary conditions on the Southern Hemisphere atmospheric circulation during the last glacial maximum

2008 ◽  
Vol 23 (4) ◽  
pp. 490-500
Author(s):  
F. Justino ◽  
E. Souza ◽  
M. C. Amorim ◽  
P. L. Silva Dias ◽  
C. F. Lemos
Keyword(s):  
Boundary Conditions ◽  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Specific Humidity ◽  
Climate Simulation ◽  
Last Glacial ◽  
Climate Anomalies ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Based upon coupled climate simulations driven by present day and glacial boundary conditions, we demonstrate that although the ice sheet topography modifications during the glacial period are primarily placed in the Northern Hemisphere (NH), a climate simulation that employs the ICE-5G glacial topography delivers significantly enhanced climate anomalies in the Southern Hemisphere (SH) as well. These conditions, in association with climate anomalies produced by the modification of the atmospheric CO² concentration characteristic of the Last Glacial Maximum (LGM) interval, are shown to be the primary forcing of the SH climate during this epoch. Climate anomalies up to -6°C over the Antarctic region and -4°C over South America are predicted to occur in respect to present day conditions. Accompanying the SH cooling in the LGM simulation there exists a remarkable reduction in the specific humidity, which in turn enforces the overall Southern Hemisphere cooling due to the weaker greenhouse capacity of the dry atmosphere.

scholarly journals The Last Glacial Maximum and deglaciation in central Patagonia, 44°S–49°S

2017 ◽  
Vol 43 (2) ◽  
pp. 719 ◽  
Author(s):  
M. Mendelova ◽  
A.S. Hein ◽  
R. McCulloch ◽  
B. Davies
Keyword(s):  
Southern Hemisphere ◽  
Last Glacial Maximum ◽  
Environmental Changes ◽  
Convincing Evidence ◽  
Glacial Maximum ◽  
Future Research ◽  
Last Glacial ◽  
The Antarctic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

This paper reviews published geochronological data on glacier fluctuations and environmental changes in central Patagonia (44° S - 49° S) from the Last Glacial Maximum (LGM) through to the Holocene. Well-dated glacial chronologies from the southern mid-latitudes can inform on the synchronicity of glacial advances worldwide and provide insight on the drivers of southern hemisphere glaciations. In central Patagonia, two large outlet lobes of the former Patagonian Ice Sheet advanced in broad synchrony with the global LGM. In contrast to other parts of Patagonia, there is no convincing evidence for a more extensive local LGM advance during Marine Isotope Stage 3. Deglaciation initiated at ca. 19 ka, earlier than in other parts of Patagonia and regionally in the Southern Hemisphere, and rapid deglaciation saw ice margins retreat in places by at least 80-120 km within a few millennia. The Lateglacial glacier margins are poorly constrained, but an ice mass substantial enough to maintain a large regional proglacial lake must have persisted at this time. The timing of lake drainage and opening of the Río Baker drainage route to the Pacific Ocean is debated; the only directly dated shoreline suggests this occurred at the end of the Antarctic Cold Reversal at 12.7 ka. Palaeoecological evidence for cooling during the Antarctic Cold Reversal or Younger Dryas remains equivocal, which may reflect both the eurythermic nature of Patagonian vegetation and shifting Southern Westerly Winds. Eastern outlet glaciers appear to have advanced or stabilised at the Lateglacial/Holocene transition when palaeoenvironmental records indicate warmer and drier conditions, but the reason for this is unclear. Our review reveals both spatial and temporal gaps in available data that provide avenues for future research.

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