INVESTIGADORES
VERA Carolina Susana
artículos
Título:
The Nature of a Heat Wave in Eastern Argentina Occurring during SALLJEX
Autor/es:
CERNE, BIBIANA; VERA, CAROLINA; LIEBMANN, BRANT
Revista:
MONTHLY ENERGY REVIEW
Editorial:
American Meteorological Society
Referencias:
Lugar: Boston, Ma, USA; Año: 2007 vol. 135 p. 1165 - 1174
ISSN:
0027-0644
Resumen:
This note describes the physical processes associated with the occurrence of a heat wave over centralArgentina during the austral summer of 2002/03, during which the South American Low-Level Jet Experiment(SALLJEX) was carried out. The SALLJEX heat wave that lasted between 25 January and 2February 2003 was punctuated by extreme conditions during its last 3 days, with the highest temperaturerecorded over the last 35 yr at several stations of the region. It was found that not only the activity ofsynoptic-scale waves, but also the intraseasonal oscillation variability, had a strong impact on the temperatureevolution during this summer. During the weeks previous to the heat wave development, an intensifiedSouth Atlantic convergence zone (SACZ) dominated the atmospheric conditions over tropical SouthAmerica. Temperatures started to increase in the subtropics due to the subsidence and diabatic warmingassociated with the SACZ, as depicted by SALLJEX upper-air observations. An extratropical anticyclonethat evolved along southern South America further intensified subsidence conditions. By the end of Januarythe warming processes associated with SACZ activity weakened, while horizontal temperature advectionbegan to dominate over central Argentina due to the intensification of the South American low-level jet.This mechanism led to temperature extremes by 2 February with temperature anomalies at least twostandard deviations larger than the climatological mean values. Intense solar heating favored by strongsubsidence was responsible for the heat wave until 31 January, after which horizontal temperature advectionwas the primary process associated with the temperature peak.