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

• Autor(a) principal: Justino,F.
• Data de Publicação: 2008
• Outros Autores: Souza,E., Amorim,M. C., Dias,P. L. Silva, Lemos,C. F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Meteorologia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862008000400008
• topic: Last Glacial Maximum; Climate Changes; Baroclinic activity; CO²

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.