INVESTIGADORES
VERA Carolina Susana
artículos
Título:
An Observed Trend in Central South American Precipitation.
Autor/es:
LIEBMANN, BRANT; VERA, CAROLINA; CARVALHO, LEILA; CAMILLONI, INES; HOERLING, MARTIN; ALLURED, DAVID; BARROS, VICENTE; BAEZ, JULIAN; BIDEGAIN, MARIO
Revista:
JOURNAL OF CLIMATE
Editorial:
American Meteorological Society
Referencias:
Lugar: Boston, Estados Unidos; Año: 2004 vol. 17 p. 4357 - 4367
ISSN:
0894-8755
Resumen:
Seasonal linear trends of precipitation from South American station data, which have been averaged onto
grids, are examined, with emphasis on the central continent. In the period 197699, the largest trend south of
208S occurs during the JanuaryMarch season, is positive, and is centered over southern Brazil. From 1948 to
1975 the trend is also positive, but with less than half the slope. The trend is not due to a systematic change
in the timing of the rainy season, which almost always starts before January and usually ends after March, but
rather results from an increase in the percent of rainy days, and an increase in the rainy day average. The
dynamic causes of the trend are not obvious. It does not appear to be accounted for by an increase in synoptic
wave activity in the region. The precipitation trend is related to a positive sea surface temperature trend in the
nearby Atlantic Ocean, but apparently not causally. The trend in the Atlantic seems to result from a decrease
in mechanical stirring and coastal upwelling associated with a decrease in the strength of the western edge of
the circulation associated with the South Atlantic high.8S occurs during the JanuaryMarch season, is positive, and is centered over southern Brazil. From 1948 to
1975 the trend is also positive, but with less than half the slope. The trend is not due to a systematic change
in the timing of the rainy season, which almost always starts before January and usually ends after March, but
rather results from an increase in the percent of rainy days, and an increase in the rainy day average. The
dynamic causes of the trend are not obvious. It does not appear to be accounted for by an increase in synoptic
wave activity in the region. The precipitation trend is related to a positive sea surface temperature trend in the
nearby Atlantic Ocean, but apparently not causally. The trend in the Atlantic seems to result from a decrease
in mechanical stirring and coastal upwelling associated with a decrease in the strength of the western edge of
the circulation associated with the South Atlantic high.