The impact of land use changes over the low level circulation related to the Northwestern Argentinean low

FERREIRA LORENA; SAULO ANDREA CELESTE; RUIZ JUAN; SELUCHI MARCELO

Foz de Iguazu, Brasil

Conferencia; 8th International Conference on Southern Hemisphere Meteorology and oceanography; 2006

American Meteorological Society

The Northwestern Argentinean Low (NAL) is a low pressure system with its center located approximately at 66ºW- 30ºS, close to the eastern Andean slopes. Previous studies show that NAL life cycle and position is strongly conditioned by the heat budget at the surface (particularly during the warm season). This leads to the hypothesis that NAL could be very sensitive to changes of surface parameters which ultimately modulate the surface heat balance. In order to investigate land/ atmosphere interactions over the NAL and surrounding areas, several sensitivity studies employing different land use and soil moisture patterns are proposed. They have been done using WRF (Weather Research and Forecasting) model, for a particular NAL episode observed during SALLJEX (South America Low level jet experiment). Results reveals a strong sensitivity to an augmentation of soil dryness that causes a deepening of the NAL and an acceleration of the northerly flow to the east of the NAL. This kind of response also leads to a change in the position of the related precipitation area.