TY - JOUR
T1 - Deep convection east of the Andes Cordillera
T2 - A test case analysis of airmass origin
AU - Teitelbaum, Hector
AU - Le Treut, Hervé
AU - Moustaoui, Mohamed
AU - Cadrera, Gustavo C.
AU - Ibañez, Guillermo
PY - 2008
Y1 - 2008
N2 - Warm and moist air masses, required to generate deep convection east of the Andes Cordillera, are generally the result of humidity transport by the so-called low-level jet (LLJ). In this paper, it is shown from detailed test cases that the eastern part of the continent and the adjacent Atlantic Ocean may constitute another source of moist, warm air, which could be of potential importance even in the presence of a southerly LLJ. The position of the anticyclones crossing South America from the Pacific Ocean to the Atlantic Ocean appears to be a key factor affecting the origin of moisture over the continent. In particular, the LLJ may weaken and even change its direction when the eastern side of the South Pacific anticyclone crosses the mountains; this wind reversal is generally associated with deep convection suppression. Thus, as a South Pacific anticyclone crosses the continent more to the east and its western side reaches the east coast of South America, deep convection can reappear east of the Andes, over the Mendoza region, although the LLJ is frequently suppressed. This is associated with a transport of warm and moist air from Uruguay, southeast Brazil, or even directly from the Atlantic Ocean.
AB - Warm and moist air masses, required to generate deep convection east of the Andes Cordillera, are generally the result of humidity transport by the so-called low-level jet (LLJ). In this paper, it is shown from detailed test cases that the eastern part of the continent and the adjacent Atlantic Ocean may constitute another source of moist, warm air, which could be of potential importance even in the presence of a southerly LLJ. The position of the anticyclones crossing South America from the Pacific Ocean to the Atlantic Ocean appears to be a key factor affecting the origin of moisture over the continent. In particular, the LLJ may weaken and even change its direction when the eastern side of the South Pacific anticyclone crosses the mountains; this wind reversal is generally associated with deep convection suppression. Thus, as a South Pacific anticyclone crosses the continent more to the east and its western side reaches the east coast of South America, deep convection can reappear east of the Andes, over the Mendoza region, although the LLJ is frequently suppressed. This is associated with a transport of warm and moist air from Uruguay, southeast Brazil, or even directly from the Atlantic Ocean.
UR - http://www.scopus.com/inward/record.url?scp=49749133549&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=49749133549&partnerID=8YFLogxK
U2 - 10.1175/2007MWR2088.1
DO - 10.1175/2007MWR2088.1
M3 - Article
AN - SCOPUS:49749133549
SN - 0027-0644
VL - 136
SP - 2201
EP - 2209
JO - Monthly Weather Review
JF - Monthly Weather Review
IS - 6
ER -