@Article{SauloSeluNico:2004:CaStCh,
author = "Saulo, A. Celeste and Seluchi, Marcelo Enrique and Nicolini,
Matilde",
affiliation = "{CPTEC-INPE-Cachoeira Paulista-12630-000-SP-Brasil}",
title = "A case study of a Chaco Low Level Jet event",
journal = "Monthly Weather Review",
year = "2004",
volume = "132",
number = "11",
pages = "2669--2683",
month = "nov.",
abstract = "This paper concentrates on the analysis of the life cycle of the
low level jet (LLJ) during a summer Chaco Jet event. This is
accomplished through the use of the Eta/CPTEC (Centro de
Previs{\~a}o del Tempo e Estudos Clim{\'a}ticos) regional model,
in order to obtain high temporal and spatial detail of the main
processes taking place. Both the low level circulation and the
geopotential height evolution at different latitudes are analyzed
to provide a more detailed description of the effects of
topography and differential warming on the evolution of this
current. This study shows that the life cycle of the particular
event analyzed, is not the same at the different latitudes swept
by this well organized northerly current, expanding from 15šS to
32šS during two consecutive days. A common feature to all the
examined latitudes is the presence of a diurnal cycle linked to
local effects which is more evident during the first day and a
half of the simulation. This cycle was identified not only by a
nocturnal maximum of the wind, but also by the oscillations of the
geostrophic wind close to the surface in response to differential
warming over sloping terrain. However, during the second day, the
diurnal oscillation is superseded by synoptic scale forcing. The
meridional growth of this northerly current reacts basically to a
deepening of the Northwestern Argentina Low, consequently being a
geostrophic response to a synoptic perturbance. However, during
the final stages of this event, a northerly wind area located over
the 3 southern tip of the current, which notably increases the
northerlies penetration toward higher latitudes, develops. This
last extension is mainly due to a component of ageostrophic
origin. Evidence is provided in support to the hypothesis that
this secondary development as a feedback between the LLJ and the
precipitation at the exit region.",
copyholder = "SID/SCD",
issn = "0027-0644",
language = "en",
targetfile = "Saulo_A case study of a Chaco.pdf",
urlaccessdate = "25 abr. 2024"
}