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1. Introduction Since the investigations of Zhou and Lau (1998) on the monsoon system in South America, several studies have addressed the subject, mainly related to precipitation and circulation regimes over the continent. A review of the fundamental features related to this system over South America was documented in Vera et al. (2006) and Nogués-Paegle et al. (2002) . Although there is not an obvious reversal of winds over large areas of South America, as occurs in Asia and India, it is
1. Introduction Since the investigations of Zhou and Lau (1998) on the monsoon system in South America, several studies have addressed the subject, mainly related to precipitation and circulation regimes over the continent. A review of the fundamental features related to this system over South America was documented in Vera et al. (2006) and Nogués-Paegle et al. (2002) . Although there is not an obvious reversal of winds over large areas of South America, as occurs in Asia and India, it is
to distinguish changes expected due to external forcings. Uncertainties in local forcings and feedbacks also make it difficult to estimate the contribution of greenhouse gas increases to observed small-scale temperature changes ( Bernstein et al. 2007 ). Climate change has been studied over South America (SA) (60°S–10°N, 90°–20°W) mainly in the context of deforestation in the Amazon ( Malhi et al. 2008 ; Nobre et al. 1991 ). There have been few studies about climate change that consider the
to distinguish changes expected due to external forcings. Uncertainties in local forcings and feedbacks also make it difficult to estimate the contribution of greenhouse gas increases to observed small-scale temperature changes ( Bernstein et al. 2007 ). Climate change has been studied over South America (SA) (60°S–10°N, 90°–20°W) mainly in the context of deforestation in the Amazon ( Malhi et al. 2008 ; Nobre et al. 1991 ). There have been few studies about climate change that consider the
1. Introduction Significant relationships exist between the Atlantic Ocean and climate variability in South America and Africa ( Nobre et al. 2006 ; Reason et al. 2006 ; Grimm and Zilli 2009 ). However, teleconnections between South American and African climate are poorly understood. Through AGCM simulations, K. Cook et al. (2004) concluded that South America and Africa influence each other’s climate and suggested a stronger influence of Africa on South America. The influence of South
1. Introduction Significant relationships exist between the Atlantic Ocean and climate variability in South America and Africa ( Nobre et al. 2006 ; Reason et al. 2006 ; Grimm and Zilli 2009 ). However, teleconnections between South American and African climate are poorly understood. Through AGCM simulations, K. Cook et al. (2004) concluded that South America and Africa influence each other’s climate and suggested a stronger influence of Africa on South America. The influence of South
1. Introduction South America features some of the most extreme convective cloud systems on the planet. Zipser et al. (2006) have pointed out that some of the deepest convective systems on Earth occur in Argentina near the Andes. Garstang et al. (1994) showed that some of the largest squall lines in the world occur over the Amazon region. These extreme vertical and horizontal structures occur in a region where massive topography and complex land surface characteristics affect the convection
1. Introduction South America features some of the most extreme convective cloud systems on the planet. Zipser et al. (2006) have pointed out that some of the deepest convective systems on Earth occur in Argentina near the Andes. Garstang et al. (1994) showed that some of the largest squall lines in the world occur over the Amazon region. These extreme vertical and horizontal structures occur in a region where massive topography and complex land surface characteristics affect the convection
upper-level information to observe the trough precursor. Studies of South American cyclogenesis have shown that mid- and upper-level troughs are present in all cases analyzed by Gan and Rao (1996) , Innocentini and Caetano Neto (1996) , Marengo et al. (1997) , Seluchi and Saulo (1998) , Vera et al. (2002) , and Funatsu et al. (2004) . The synoptic conditions associated with South American cyclogenesis were studied by Seluchi (1995) in 54 cases from 1980 to 1984. The results showed that
upper-level information to observe the trough precursor. Studies of South American cyclogenesis have shown that mid- and upper-level troughs are present in all cases analyzed by Gan and Rao (1996) , Innocentini and Caetano Neto (1996) , Marengo et al. (1997) , Seluchi and Saulo (1998) , Vera et al. (2002) , and Funatsu et al. (2004) . The synoptic conditions associated with South American cyclogenesis were studied by Seluchi (1995) in 54 cases from 1980 to 1984. The results showed that
1. Introduction Greenhouse gases such as carbon dioxide are accumulating, and concentrations have more than doubled since the eighteenth century due to industrial and agricultural emissions ( IPCC 2021 ). Over 1 Pg yr −1 of smoke is released into the atmosphere through biomass burning, of which about two-thirds is from the tropics ( Andreae 2019 ). South America has almost 0.5 billion people and an agricultural sector contribution of $200 billion involving forest-to-farm conversion ( Artaxo et
1. Introduction Greenhouse gases such as carbon dioxide are accumulating, and concentrations have more than doubled since the eighteenth century due to industrial and agricultural emissions ( IPCC 2021 ). Over 1 Pg yr −1 of smoke is released into the atmosphere through biomass burning, of which about two-thirds is from the tropics ( Andreae 2019 ). South America has almost 0.5 billion people and an agricultural sector contribution of $200 billion involving forest-to-farm conversion ( Artaxo et
of South America during the different phases of the El Niño–Southern Oscillation (e.g., Ropelewski and Halpert 1987 , 1989 ; Aceituno 1988 ; Rao and Hada 1990 ; Grimm et al. 1998 , 2000 ; Grimm 2003 , 2004 ). Given the dependence of monthly to seasonal precipitation amounts on the frequency of extreme precipitation events, it is reasonable to expect the frequency of extreme rainfall events to be modulated by ENSO in some preferred locations. However, this does not mean that regions with
of South America during the different phases of the El Niño–Southern Oscillation (e.g., Ropelewski and Halpert 1987 , 1989 ; Aceituno 1988 ; Rao and Hada 1990 ; Grimm et al. 1998 , 2000 ; Grimm 2003 , 2004 ). Given the dependence of monthly to seasonal precipitation amounts on the frequency of extreme precipitation events, it is reasonable to expect the frequency of extreme rainfall events to be modulated by ENSO in some preferred locations. However, this does not mean that regions with
1. Introduction Based on observational data and model analyses a number of papers have shown a northerly flow, located to the east of the Andes, is responsible for the significant transport of humidity and heat into the southeastern South American region ( Nogués-Paegle and Mo 1997 ; Douglas et al. 1998 ; Paegle 2000 ; Nicolini and Saulo 2000 ; Salio et al. 2002 ; Marengo et al. 2002 , 2004 ; Liebmann et al. 2004 , among others). This region, usually referred to as southeastern South
1. Introduction Based on observational data and model analyses a number of papers have shown a northerly flow, located to the east of the Andes, is responsible for the significant transport of humidity and heat into the southeastern South American region ( Nogués-Paegle and Mo 1997 ; Douglas et al. 1998 ; Paegle 2000 ; Nicolini and Saulo 2000 ; Salio et al. 2002 ; Marengo et al. 2002 , 2004 ; Liebmann et al. 2004 , among others). This region, usually referred to as southeastern South
afforestation experiments in the midlatitudes of the Northern Hemisphere have reduced the surface albedo, leading to tropical circulation changes and a drying at the southern edge of the Amazon forest ( Swann et al. 2012 ). Other papers demonstrate how ice ( Chiang and Bitz 2005 ) or anthropogenic aerosol forcing ( Rotstayn et al. 2000 ) may cause changes in midlatitude energy budgets and tropical circulation. Rainfall in South America is dependent on the southward movement of the ITCZ, which allows wet
afforestation experiments in the midlatitudes of the Northern Hemisphere have reduced the surface albedo, leading to tropical circulation changes and a drying at the southern edge of the Amazon forest ( Swann et al. 2012 ). Other papers demonstrate how ice ( Chiang and Bitz 2005 ) or anthropogenic aerosol forcing ( Rotstayn et al. 2000 ) may cause changes in midlatitude energy budgets and tropical circulation. Rainfall in South America is dependent on the southward movement of the ITCZ, which allows wet
. 2003 ), and longer time scales. Fig . 1. (top) Selected regions and annual cycles of precipitation in South Africa. (middle)–(bottom) The 1° boxes in South America with precipitation significantly correlated to the lagged precipitation (5 days) in each selected region in South Africa. Dark squares (triangles) indicate confidence levels higher than 90% for positive (negative) correlation; open squares (triangles) are for confidence levels between 85% and 90%. Ellipses indicate the regions with
. 2003 ), and longer time scales. Fig . 1. (top) Selected regions and annual cycles of precipitation in South Africa. (middle)–(bottom) The 1° boxes in South America with precipitation significantly correlated to the lagged precipitation (5 days) in each selected region in South Africa. Dark squares (triangles) indicate confidence levels higher than 90% for positive (negative) correlation; open squares (triangles) are for confidence levels between 85% and 90%. Ellipses indicate the regions with
