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.

High-resolution climate simulation of the last glacial maximum

2007 ◽  
Vol 31 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Seong-Joong Kim ◽  
Thomas J. Crowley ◽  
David J. Erickson ◽  
Bala Govindasamy ◽  
Phillip B. Duffy ◽  
...  
Keyword(s):  
High Resolution ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Climate Simulation ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

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 Committed and projected future changes in global peatlands – continued transient model simulations since the Last Glacial Maximum

2021 ◽  
Vol 18 (12) ◽  
pp. 3657-3687
Author(s):  
Jurek Müller ◽  
Fortunat Joos
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Future Scenarios ◽  
Dynamic Global Vegetation Model ◽  
Last Glacial ◽  
Climate Anomalies ◽  
The Future ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Peatlands are diverse wetland ecosystems distributed mostly over the northern latitudes and tropics. Globally they store a large portion of the global soil organic carbon and provide important ecosystem services. The future of these systems under continued anthropogenic warming and direct human disturbance has potentially large impacts on atmospheric CO2 and climate. We performed global long-term projections of peatland area and carbon over the next 5000 years using a dynamic global vegetation model forced with climate anomalies from 10 models of the Coupled Model Intercomparison Project (CMIP6) and three standard future scenarios. These projections are seamlessly continued from a transient simulation from the Last Glacial Maximum to the present to account for the full transient history and are continued beyond 2100 with constant boundary conditions. Our results suggest short to long-term net losses of global peatland area and carbon, with higher losses under higher-emission scenarios. Large parts of today's active northern peatlands are at risk, whereas peatlands in the tropics and, in case of mitigation, eastern Asia and western North America can increase their area and carbon stocks. Factorial simulations reveal committed historical changes and future rising temperature as the main driver of future peatland loss and increasing precipitations as the driver for regional peatland expansion. Additional simulations forced with climate anomalies from a subset of climate models which follow the extended CMIP6 scenarios, transient until 2300, show qualitatively similar results to the standard scenarios but highlight the importance of extended transient future scenarios for long-term carbon cycle projections. The spread between simulations forced with different climate model anomalies suggests a large uncertainty in projected peatland changes due to uncertain climate forcing. Our study highlights the importance of quantifying the future peatland feedback to the climate system and its inclusion into future earth system model projections.

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.

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