Procesos dinamicos y termodinamicos responsables del desarrollo de un sistema de baja segregada

ALEJANDRO A. GODOY, NORMA E. POSSIA, CLAUDIA M. CAMPETELLA Y YANINA GARCIA SKABAR

REVISTA BRASILEIRA DE METEOROLOGIA

SBMet

Año: 2011 vol. 26 p. 503 - 514

0102-7786

ABSTRACT: A CASE OF CUTT-OFF LOW IN SOUTHERN SOUTH AMERICA: DYNAMIC AND THERMODYNAMIC PROCESSES The dynamic and thermodynamic processes involved in the life cycle of a cutoff low occurred in March 2007 were studied. These processes are analyzed through the terms of the vorticity and thermodynamic equations using a set of analysis generated with the BRAMS model. The main processes that explain the segregation of the subtropical part of the trough are the horizontal advection of cyclonic vorticity at high levels and horizontal warm advection at middle levels, both over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. The increased intensity of the upper level low pressure system is mainly explained by intensification of both ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity and this explains the stagnation of cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. The dynamic and thermodynamic processes involved in the life cycle of a cutoff low occurred in March 2007 were studied. These processes are analyzed through the terms of the vorticity and thermodynamic equations using a set of analysis generated with the BRAMS model. The main processes that explain the segregation of the subtropical part of the trough are the horizontal advection of cyclonic vorticity at high levels and horizontal warm advection at middle levels, both over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. The increased intensity of the upper level low pressure system is mainly explained by intensification of both ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity and this explains the stagnation of cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. A CASE OF CUTT-OFF LOW IN SOUTHERN SOUTH AMERICA: DYNAMIC AND THERMODYNAMIC PROCESSES The dynamic and thermodynamic processes involved in the life cycle of a cutoff low occurred in March 2007 were studied. These processes are analyzed through the terms of the vorticity and thermodynamic equations using a set of analysis generated with the BRAMS model. The main processes that explain the segregation of the subtropical part of the trough are the horizontal advection of cyclonic vorticity at high levels and horizontal warm advection at middle levels, both over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. The increased intensity of the upper level low pressure system is mainly explained by intensification of both ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity and this explains the stagnation of cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. The increased intensity of the upper level low pressure system is mainly explained by intensification of both ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity and this explains the stagnation of cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. The analysis of the trajectories of parcels, assuming the conservation of potential vorticity, allowed the detection of stratospheric air entry to middle levels of the lower troposphere around the cut-off low. Keywords: cutoff low, life cycle, dynamic and thermodynamic processescutoff low, life cycle, dynamic and thermodynamic processes